@vickidoodah and @Westofeasttoday you both just sound quite mean tbh, and not someone I'd really want my children to have to spend time with! Do you not care about these children? If you don't then why are you spending time with them/going out of your way to interact with them? And if you do then surely you care more about how they are feeling than whether they have met some arbitrary adult standard of "correct behaviour"?
My nephew, who has known me since he was born (now 8) didn't want to say hello to me when he came to my house last week. Did I care/get angry/annoyed? No of course not! I just wondered if he was OK, if we'd left it too long between visits, if he was knackered from half term activities etc. SIL was doing the whole performative parenting thing you seem to be such a fan of: "X, say hello to auntie Conker, don't be rude!" while he was hiding behind her. I was just thinking "leave the poor boy alone, he'll warm up in a minute!" And of course he did, after getting his bearings, settling in and me setting up a game which he could choose to join in with or not. He then didn't want to say goodbye or thank you for having me. Totally fine! I knew he'd had a good time just by watching him interact with us and DC, I didn't need his verbal validation of it as well! Would have been totally meaningless hearing him parrot it out after being forced to by mum or dad!
This way I'm actually building a relationship with him and taking his feelings into consideration rather than being annoyed that my "right" to be acknowledged as an adult has been defied. Sounds like a horrible transactional way to treat people. Who cares if a random kid at swimming club doesn't say hi to you?! I also feel very strongly that girls shouldn't be forced to say hi to people when they don't want to. Girls are socialised to ignore any bad feelings they might have about someone and instead act to "please" that adult. Cause for plenty of abuse and we'd be doing young girls a much bigger favour if we taught them to trust their gut and avoid/ignore anyone they don't want to interact with.
And no, I wasn't a feral child - I was one whose mum insisted on me always saying please and thank you. All it did was gain her the benefit of people telling her what wonderfully polite children she had. Didn't build any sort of relationship between me and her or me and these adults and doesn't seem to have benefitted me in any way - in fact it taught me to be a bit of a people pleaser and not feel like I could be "rude" to sleazy men.