Yes.
A lot of you will hate me for this...
Hopefully not, I don't. Disagree strongly != hate.
MS doing this is them trying to ensure that Firefox will work with their web apps (or, web apps built with their technology).
Great, if I wanted it I would seek it out, download it and install it. I think most people that go with firefox understand that some MS technologies don't quite work with it in all cases. Genuine windows crap comes to mind.
Now, granted that they are taking liberties they should not.
Many people use firefox to get away from Microsoft. Understand that what MS is doing here is blasphemy to many. Actions like this reinforce the "MS is evil" notion. If a firefox update installed something into IE without asking or without an uninstall, I would be offended too.
On the other hand MS is trying to make the browsing experience BETTER for people who use .Net with Firefox.
The ends do not justify the means. Oh shit, I forgot this is slashdot, ignore that comment.
I'm not so sure this is a bad thing.
If it is not bad for you, good. I do not doubt that many people will not care about this. For many of us this is bad. I personally do not like anything (iTunes, Java, etc) that installs components without my approval.
Look, if you were running Ubuntu, installed Opera, and automatically got plugins from Synaptic for Opera that added new functionality would you complain?
If it came from Opera, no. If it came from another source, yes I would complain. Your example is a bit different. If Windows had something like Synaptic, and I got firefox through it, I wouldn't be surprised if they pushed an update that modified it. But I didn't get firefox through a MS service. Your comparison fails. I compile my own firefox for both Windows and Linux, for optimization and more control. I don't fully trust Synaptic for everything either.