Of course, I don't think that the way patents are currently treated in the US is the best way to handle it... and I think it's very safe to say that the interests of the public software crowd are very far from the hearts and minds of the people in charge of dealing with those issues. However, there are a couple of issues to keep in mind:
Just because these guys charge money to MSFT doesn't mean they have to charge money to the Moz team. The idea that it has to be the same price for everyone is a myth. Not only that, but MSFT couldn't turn around and use the fact that the Moz team is getting it for free as evidence that they should get it for free either. Price differentials based on the customer is a time-honoured tactic.
OTOH, they would ALSO be free to turn around and charge AOL for their branded version of Mozilla. Just because the software codebase is basically the same doesn't mean that there aren't in fact two different entities involved.
In fact, this is pretty much how I expect it to play out.
Of course, if these guys do get rapacious, then perhaps it can be a catalyst for getting the current very dumb approach to patent and IP in general in the US changed.
I've pretty much moved on to the place where I think "bring on the abuses... work it ever harder boys" with the idea that the sooner the greedheads overload the system, the sooner it will break down and become obvious to everyone but the pathologically greedy that the pathologically greedy need to be taken in hand.