I think it's too bad that people seem determined to see this in a negative light, instead of as an opportunity.
I want to reiterate though, that since all this is STILL UNFOLDING, there is a lot of speculation, and very little fact. All that we really know is that id released some games on Steam, and some of those games use DosBox 0.70 with some critical changes. That's it.
It may well be that they did all this without contacting the DosBox team, but until the whole team can verify that they weren't contacted by anyone for this purpose, and as long as they aren't forgetting that they were contacted, this is still speculation. And as far as I know, only part of the team has spoken about this. It may very well be in the DosBox team's best interest then to make sure that this is a fact, instead of just speculation before you get too deep into this.
There's no evidence that it was id who chose to do this. In fact, it is more likely that Activision is the one directly responsible, but it's still speculation as to who is responsible.
And as far as I can tell, no one is blaming DosBox for the problems that are happening. It's way too early to tell, and it's really just speculation. To give this as a reason for being upset is not really being fair. I know you're upset, but it would appear that the reason is more that your team wasn't contacted before this happened, and that the implementation was poor.
Rather than focusing on areas that are speculative and unclear at this point, you should probably focus on finding out for sure if the DosBox team was contacted or not. Additionally, you should be trying to decide on how to deal with the implementation problems. I suggested that you should negotiate with Valve for a full release of DosBox on Steam to fix the implementation problems, but you are still very much able to simply pull DosBox out from under them if that's what you really want. Whatever you decide on, I hope you think about it before you leap into action.