Yes, we know kids will play the game. You believe it's an actual decent decision to parent for people. That's why you won't find any grounds to agree with people who want options.
Skype is an option that I'm sure you're all privy too.
Options increase risk, and Nintendo want to protect their ecosystem. There's a 7 (or 10) on the box and they want to make sure there is no content in Splatoon that will offend 7+ year olds, so they're reducing options. 'Won't somebody think of the children'-worthy? Sure.
I think it's a responsible thing for Nintendo to have done. Perhaps a little antiquated but done for the best protection of children. There isn't an alternative that's is as effective as this is at reducing potential harassment towards children.
I also understand being annoyed at it but I do think it is reasonable and appropriate.