Why do people think Minecraft is just for little kids?

It's a regular game and just because it isn't M-rated seems to make a lot of people think it's a game just for a bunch of immature 6 year olds.

A lot of people consider it really weird for 14-15 year olds to "still" be playing Minecraft and there seem to be a lot of people who are hating on Minecraft.

Why is there this perception that it's a little kid game and why do people think 15 year olds are far too old to play it?

It's too easy.

Since it's kid-friendly, and most kids play it, older people say that it is for "9 year olds" and older kids shouldn't be playing it. Also, other people would consider it as boring, compared to other games such as Cod, Subnautica, Titanfall, or any other shooting game, which isn't kid-friendly