You must hate many people then, since a significant amount of media content has some sort of rating to suggest an appropriate age for the targeted audience. This is because there are people, often adults, that support the idea of restricting mature themes from young minds for a responsible, healthy development in their age groups. If you do not like how the ESRB supports people like those, perhaps you should contact them.
As I stated earlier, children and thus, their age, do not necessarily correlate to their performance. This is easily supported by the amount of players that are children, but are at high ranks, such as S and S+. There was even a poll on Squidboards to determine both the average age and rank of each member (somewhere in the General Discussion board). If your performance was good, but you still lose, then performing better is your next goal. Look for ways to improve your gameplay instead of blaming it on others, since that benefits no one.
Ranked Battles are exactly what you are talking about then, if you want to be ranked in relation to performance. Nintendo has already implemented this in Splatoon, so unless you are still below level 10, it should be your next destination. As for the two options you mentioned, they should still be there if you simply accept them as choices still. Selling games can still be done at an old age, and improving should still be an option unless you have given up.
As for your comment about Nintendo, they have other games if you have unpleasant feelings about Splatoon. Recently there have been remakes, which are dedicated to nostalgic fans, such as Wind Waker HD, Megaman Legacy Collection, etc. I am quite sure that is how Nintendo would show they care about their old fanbase.
