No harm in telling him he's being rude when he says such things. I would. And if he carried on I'd pick him up on it with "Don't be rude" or, possibly just "Oy!" Just as one teaches a child to say thank you when given something by giving a little "ahem!" reminder when they don't, or by simply not letting go of whatever it is until they say the polite thing.
I think too many of us want to be liked by children rather than respected. I think liking is less important in the long run because you can be respectful even to people you don't like. Telling someone, even at the age of six, that you hate them and that you didn't enjoy some treat they'd organised for you, is unacceptable. He needs to know that.
Angela Rayner cleared by HMRC. What a coincidence!
. He's a boy FGS..... like Sark they exaggerate magnificently, especially at his age. My GS informed me in John Lewis this week, it was 'the best day of his life'.... he was riding on the escalator! Equally with his 'hates'. The OP should ignore it and not waste time getting upset.
