I personally find it more weird that in most of the world it’s still illegal to marry someone of the same sex and that being gay would likely get you disowned if not murdered and/or raped and that most of Europe only started legalizing it in the last 10 years.
So, should people care about a 11yo sexuality? No. But most parents do. They do care if they happen to be gay, and there tend to be a massive amount of pressure for kids to be straight.
I knew I was gay since I was 3. But it took me another 14 years to come out (initially as bisexual, not because I liked men but because I was fighting against being a lesbian as bisexual was still giving hope to others I could be with a man while me being with a woman not being perceived as “as weird”.) I didn’t need a party but it would have been nice in the sense that if I knew I was being supported by my family to the point they would have wanted to celebrate me for being me, I probably wouldn’t have spent a couple of years forcing myself to sleep with men in the hope I would like it and be “normal.”
personally I find it weird that people nitpick everything linked to the LGBTQ+ community. A kid thinking they are gay and changing their mind later down the line isn’t going to hurt anyone, but the heteronormative world in which we live, where being straight is something assumed as the norm, where gay kids have no or extremely little representation in the media (in general but especially targeted to their age group, despite most kids cartoon having a romantic trope between a male/female character), where getting married to someone of the same sex is still either illegal or punishable by law, in most countries and where, when they do feel gay they are automatically told “how would you know? You are so young.” (Something I have never heard said to straight kids who have opposite sex boyfriends and/or girlfriends in primary school) unless they are 18. Is tiring, it’s even deadly because so many queer (lesbian, bi, gay) kids/teens/adults end up killing themselves due to how horrible it is to live in the closet and how much they have been made to help themselves by society at large.
So if you find a party to celebrate a kids sexuality weird, and not everything else I have stated a lot weirder and tragic. You are the problem. Should kids need parties to celebrate their sexualities? No. But when you know that same sex marriage only got legalized and took effect in England less than 10 years ago. Is it really that weird/ bad, to support a kid who feel is gay? and if you are straight when did you know you were straight? Was it REALLY age 18 or when you lost your virginity or you simply always knew you didn’t like girls like that? It’s really not that hard to figure it out. It’s a lot harder to accept it and come out and face the world and the struggles that come with it. Hence why we celebrate it. Not because our sexualities are a big deal (who cares) but it’s because it’s such an ordeal to get to the point where we love ourselves enough to not hide or be ashamed of that part of us, that once we get there, we want to celebrate, not our sexuality as much as the acceptance process.