Even before Charlie Davies was fined on Friday, there were few out there who were unwilling to admit he dove. No sane person can see that replay and not see a player purposefully trying to deceive the referee. The one group of people you'd probably expect to defend him, though, are DC United fans.
At Black and Red United, at least, that's not entirely true. SB Nation's DC United blog goes on record as voicing their support for MLS's decision:
What CD9 did was, in a word, wrong. We'll start there. As a league, MLS really doesn't want people to dive or for there to be a reputation of diving in the league. They had to do something. Diving may be part of the game - and that's why you don't change the score post facto or alter the standings - but that doesn't mean it can't be disincentivized through punishment off the pitch. That's where the fine comes in.