People in the thread are referring to sexism and classism. I assume Christina is from a more working class background than Neil is, from the comments.
But re the sexism query, I assume that many of those responding to call him out for sexism did so because they recognised the mansplaining, the assumption that a women couldn't possible have these ideas herself.
Put it this way, OP, if you had to guess the sex of both the person writing the tweet and the person referred to, if you didn't know, what would you guess was the sex of both? Could you imagine a woman writing that to another woman? Or to a man? What about a man writing that to another man?
I think we all know that that tweet could and would only have been written by a man to a woman. Well, all of us who are women, anyway, who will recognise the patronising tone.
Are you female, OP?