>I am saying that the stereotype he detected really exists and somehow happily coexist with other stereotypes.

Of course each of us has to deal with a plethora of cultural influences and pressures, but in this case you're just asserting things and maybe gaslighting a little. Someone shared an anecdote that counteracts your assertion and you go and post hoc fit your conclusion by claiming there are in fact other secret stereotypes that must be there as well. Maybe they aren't there.

>Personally I knew plenty of boys that were not fuckups.

So do I.

In my case, however, all the fuckups I know are boys. All of them. I don't know what that anecdote says, but it says something.

OP wrote: "Strange, when I was a kid adults had the opposite attitude towards us. Boys were considered inherently mischievous, prone to cheating or making shortcuts, and always up to no good, while girls were considered rule-abiding, smart and hard-working."

Me posting first time: these stereotypes coexist.

You: You are opposing him and gasslighting. Also, he contradicted you.

Me now: wtf. Also, he could not contradict my assertion, because I joined only after him and made no assertion before.

I understand what you were trying to say. Have you considered that maybe the other stereotypes did not coexist or were not influential? That's what I'm saying.

It says something about tunnel-vission and horse blinders and so on.

On my part? Yeah. Could be.

So then? You see the mistake and keep the same view?

It isn't really about holding or not holding any specific view. I shared my personal experience. I admit the possibility that all kinds of biases could be coloring my perspective. But it is what it is.