Kids have no filter. The tendency kids have to speak their minds more than what would be socially acceptable to us adults is something we love about them. Plus, these youngsters not having social awareness is what allows them to not really give a flying fuck about what they say, which tends to make things hilarious or awkward quickly.
Can you imagine if you said everything you were thinking out loud? Youths do this everyday which is why these comments kids have said to teachers will leave you feeling weird.