Also, frankly, the inkbrush's role is not as valuable. It doesn't matter if you point out that people are judging it according to its weaknesses rather than its strengths because its niche just doesn't have as big of a place in Splat Zones. No one's trying to rag on your favorites, it's just looking at it from plain view. Chances are it'll be amazing in Rainmaker, it doesn't need to be good everywhere and this game is doing a decent job of making sure every weapon has their place. (Well...maybe not rapid blaster)
Coming from the Pokemon community where people tend to be more attached to specific Pokemon and want to use ones that just aren't very usable, I've learned to see low tier weapons/characters/etc. as tools that have different usability. While hard to use isn't a good pro or a con for literally anything, hard to win with is. If, at the highest level of play, you find that using one weapon to win is harder than using another one where skill level is relatively equal, than that warrants it being lower tier. In Smash, Ganondorf is a very cerebral character with a kit designed to destroy on punish, but Ganondorf players have to work much harder as a whole to secure their wins than Sheik players. This isn't to call any one character or the other braindead or easy mode, but because one character has more versatile tools and a better overall kit, winning just comes easier and that's what's natural.
I figure Smash as a reference makes sense here, as these early tier lists discussions go about as well here as they do on Smashboards. All we're missing is lobbies so that people can say "You think Custom Splattershot is bad? 1v1 me bro."