This is completely unacceptable behaviour and I hope that bloke is jailed.
Imo, you can blame VAR for things like this happening.
It was pitched as something that would help referees. But in fact, all it's done is increase anger and mistrust of them. Howard Webb seems to be apologising every week. Clubs like Forest don't help either, with talk of corruption, conspiracy and threatening court action. You never had stuff like that happening before. That is now overspilling into things like this.
The FA need to take responsibility for the mess they've created.