I've heard lots about this negging thing recently, isn't it what misogynistic Andrew Tate fans do to try and get girls?
Yeah, it's horrible. I learned a little bit about it in my therapy sessions (narcissistic mother, a life time of trauma) bit it does seem to be really prevalent in incel communities.
They wine and dine you, flatter you then BAM a comment or remark that put you in your place.
Things like 'I can see why you think that dress looks good on you'
'You look really good in that dress and you are brave to wear it even though you look fat'
'Most girls who wear too much make up look like sluts, but you look really pretty'
Jack's version of this is 'you aren't that special but I'm prepared to give you a chance'.