Quite Sally
We always went for cheaper village hall parties so we could invite everyone in a class until strong friendship groups were sorted.
And if people think it's inevitably accidental then I am sorry but no.
DS1 struggled in mainstream and I have no lack of understanding for parents who chose not to invite him to parties, I quite get it.
Except the mum who invited everyone else, collected them from school, lined the kids up in front of ds1 deliberately, standing about 3cm in front of my face to make a point; then shouted 'nice boys from class X, to X's Party, quick march!'.
See, I am a peaceful type in general, I really am. But I never came closer to pushing someone off their five inch stilettos than on that day.
We've also had parents actively pushing then non verbal ds3 from his TA to shove their NT kids in their hands 'because you deserve help just as much, we all pay taxes', leading to ds3 returning home immediately day after day in tears, and petitions raised against ds1's inclusion way before he was aggressive in school, but the party ranks highest in my memory of awfulness. Oh there was the child DS3 adored and vice versa, whose parents were REALLY keen on the friendship when all they knew about us was that we lived in the posh bit, until they realised DS3 was a (lovely, gentle, kind) Base child.... then tried to ban the friendship in school and out.
I don't expect parents to include my kids by default, though if it's a class party exclusion is harsh and I am always happy to attend and help if asked. However, overt nasty exclusion is just twisted and sadly common based on the experiences of my SN Community friends.