“In war, resolution; in defeat, defiance; in victory, magnanimity”
-Winston Churchill.
How one behaves in condition of victory speaks more to their character than how they behave in defeat. When one has the upper hand, is in control of the situation, has claimed victory, there is no need to taunt, to insult, or to belittle. Victory has already been earned. There is no honor in the depravity of making a show of that victory.
I'd agree there are a few types of spawncamps. The only one that is valid, and not cheap, depraved, or exploitative of map designs is when mid is pressed so fully and forward, and the team outplays the other team in open combat so well, that by the endgame, mid has pressed all the way forward to enemy spawn. It is the natural development of a strong forward push throughout the match that could not be defeated.
The others occur when the matchmaker combines two teams that are fully imbalanced, be it in weapon selection or in player skill. As a result, it usually begins with a single player, the best player. Whether it's a ninja camping roller/brush/sploosh that invades and parks in the base, or a super player who comes in guns blazing right into the base early on and starts picking off teammates as they spawn. While the other 3 players are out in mid, this player picks off those respawning, or just making their way out. It usually takes up to 2 respawns to realize what's going on. By this time at least 2 people are now corralled at spawn. By now another player joins in the camp, and possibly a third. Once this point arrives, the match is likely over, and the ramainder is spent with them jumping up and down pelting your spawn shield to taunt (while one of their members lurks in mid to catch stragglers...this player, like myself, is probably avoiding the spawncamp....but still holding mid. Generally the spawncampers have unlimited frequent specials charged, and complete control of your base and/or the map.
The reason it's cheap is due to the fact that both teams were likely mismatched from the start, and as jsilva said, it's an exploit of a game design, specifically, the map layout in which there is no secure area in most maps to stage as a base of operations and exit on many maps. Maps that do provide multiple exits, like Ancho-V and Piranha provide total visibility to the enemy of where anyone is headed. and stupidly provide access to the enemy even in the escape routes. Surprise is a key element for most weapons in this game, and the map design prevents the spawncampers from being surprised. The quick superjump mechanic is what also causes spawncamps to be cheap. As they respawn, they jump back to your base, so if you can't kill ALL of them, you can't kill ANY of them.
If the camp happens as a natural progression of overpowering the enemy, it happens late game, and that's just how it works out. When it's set out as a tactic from the start, its an intentional exploit. Valid, because the game rules make it possible. But wrong, because it violates the way the game is intended to be played and is no longer a friendly game of people playing Splatoon, but a session of who can exploit the rules for their own gain. Like real life. The escape of which is the reason we're playing Splatoon to begin with.
It happens in ranked less often than TW, but still happens with frequency. The problem with it is, it flies in the face of the intended play, so while other players are preparing to play a game with one given objective, the player setting up the camp is exploiting the system to play differently. One can argue it's not against the rules, but I think the point here is that that itself is a defect and oversight. For the same reason baseballs and bats are regulated in the game to be of a certain size and weight class, if you go back far enough in baseball rules that was not the case at one time, and players were exploiting that. It was found that that broke the intended momentum and spirit of the game, and thus a rule was made for it. In Splatoon, they won't be setting that rule, so it is a choice of the player to play with the intended spirit of the game, or to seize any opportunistic solution that will benefit yourself. Clearly it is possible, and doable. But it also speaks volumes of the characters of the campers. Losing a Splatoon match is just a game. Demonstrating a weak character is a trait that lasts a lot longer than Judd's results page.
One additional thought on spawncampers: The overpowered guns blazing type, can simply not be countered. They are overpowered in the game for underpowered teammates. This happens most when an S+ player is stuck against lower rank players. The game puts them in the match with the assumption they can be countered by a team of 4 in normal play. The spawncamping breaks that principle when that player knows they're overskilled and can likely solo dominate their opponent. Takes over the base. From that point on the rest of their team has complete advantage by denying their weaker opponent ANY territory from the start. This can not be countered. The superior player is simply superior.
However the stealth camper types, I've found, are rarely actually good players. They rely on their camping as a crutch to carry them through against players they otherwise cannot defeat. This method only works for them if someone ELSE on their team is superior and can occupy the enemy team through normal combat at mid. They count on their team being strong enough to 3v4 while they're missing and setting up their hiding place. They effectively remove themselves from the game and stay safe, but then when the strong team has boxed in the enemy and the enemy decides to use an alternate route to defeat the good players in mid, the spawncamper strikes them down, and in combination with the strong opponent in mid, and the sneaky stealth camper, they're now fully boxed. But they did not do so through their own skill, but rather abused their teammates skill to hand them soft targets. While it may work well "as a team" I feel that such a strategy might have more of a place in 4v4 squads and private battles where the group determines their map strategy and weapon choice together and sets it into motion against another team's pre-planned strategy rather than abusing teammates hoping they're strong enough to do without you, and relying on the fact that disorganized random opponents won't be prepared for it. I don't feel like I'd object to that type of team strategy so much in a private clan tournament where both teams specifically planned that strategy.
I never will understand these wild comparisons. What does Splatoon have to do with real warfare? Nothing. It has nothing to do with real warfare nor the issues we face in everyday life. Why does it have to be brought up and compared to Splatoon? It doesn't make any sense and frankly, it's taking the fun out of Splatoon. I don't want to have to think about real world problems every single time that I play an innocent Nintendo game. We're talking about spawn camping in an innocent video game. Not talking about wiping out an entire race. The two aren't even comparable. I just...really don't understand. 
