A bit late since I don't frequent these forums but coming from a Bruins fans, Downie didn't throw his hands up because he wanted to get out of the fight. Downie got a double minor for a similar fight against Satan where Downie acted as Chara and Satan acted as Downie. Downie threw his hands up because he wanted Chara to get an extra penalty because Downie got an extra one for the same thing.
And about the stuff badmouthing Downie, I'd personally like to have him on the B's. He's a super pest who can chip in offensively. Sign me up, Boston needs a guy like him to get things rolling since Lucic seems to not care about throwing the body nearly as much as last season.
As soon as Chara gets involved in even a scrum the linesmen jump in. I think the NHL is afraid of some kind of incident that would bring bad publicity which is really pathetic. They definitely treat Chara different than other players.