I follow a friend of a friend on Threads and we exchange the odd comment every now and again. On Threads you can see every reply someone has made and this guy (lets call him Bob) will sometimes reply to ladies posting selfies. Nothing too leery but the odd 'hot' or 'gorgeous' type comment. These aren't people he knows by the looks of things. Bob is a smart guy and must know that other people can see this. He has a username on Threads but uses a profile photo so you can tell its him. Bob has a girlfriend although I dont know her. Bob is being an arse here right? Would you tell Bob he is an arse or would you mention it to your mutual friend? They aren't close friends but it just feels off and there's a chance I might bump into Bob and his girlfriend in the coming weeks and I dont know whether I should just mind my own business or not.