Well, perhaps more to the point, a lot of them are now saying "You say you're not going to try to revoke old uses of the OGL this week; what about next?" It doesn't matter if its personal or not for at least some people, it matters that they no longer trust WOTC (and Hasbro) not to conduct an abusive legal maneuver if they think its convenient.
To some extent, contract law is always about trust, because as noted by a couple people, it has no intrinsic force. All it does is provide you a (potential) hammer if other people in the agreement misbehave, but using that hammer is not an effort and cost free process, and no one really wants to do it (unless they're abusing process themselves and getting that hammer was the whole point).
As such, damaging trust of potential people who might want to make deals with you has a price.