I don't know about that, a non gamer happened to be in the same room while I was explaining the mechanics of Splatoon by showing a youtube clip I talked over to someone and she asked why I would play a kiddy shooter instead of CS GO like I used to before.
I'm still kinda in the 90s mindset when colorful games featuring mascot characters where the best games around (Mega Man, Banjo Kazooie, Mario, ...) but nowadays it seems that people associate games that feature simplified cartoon characters, basic geometry and all that as games specifically for kids. This means they base target age on presentation aspects, when in fact in video game terms a game for kids is something that deliberately features shallow gameplay which adults would find repetitive and not stimulating, like some of the LEGO based games are a little too one dimensional for gamers who are looking for a deep gameplay experience. But a game like Splatoon is in my mind equivalent to CS GO, there's nothing inherently more kiddy about it. However I would say the former is more kid-friendly.
If I show a clip of Duck Tales on NES as someone in my mid-20s and say this is one of my favorite gaming experiences ever they would guaranteed think I'm a weirdo who likes kiddy things, but for those who appreciate good game design know whatsup. The masses don't perceive things this way though. I'm supposed to play a QTE fest combat game like AC or a skinner box riddled game like The Division because of my age, or something.