My impression is that it's the dishonesty and theft that people have a problem with, not just being clever and outwitting people in the speculative gambling game.
And when those people get the impression that the EA movement is okay with getting money dishonestly as long as it's given it to a worthy cause, they take issue with EA.
Edit: Just thought of an analogy. Some charities do raffles, right? You can put money into the pot for a chance to win a prize, knowing that a proportion of all the money people put in goes to the charity.
But what if the charity sold a bunch of raffle tickets and then announced that they would not award a prize and all the money would go to the charity? Or what if it came out that the prize was rigged to go to someone affiliated with the charity? In this case I don't think you can say, "Well, those people chose to gamble so they consented to having their wealth taken."