MC's post is a lot less hostile than Tobin's, and it sort of makes sense: if you're going to develop add-ons for PM, you need to test your add-ons with the "stock" PM build, because that's the version 99% of PM users will use your add-on with. And that, of course, means testing on a Win 7+ system, so that "stock" PM will run on it. It doesn't mean you have to prefer the stock build - only that you have to test with it.
It's Tobin who seems to blow a gasket anytime he sees the letters "XP" together. Chill out, man! Whatever your feelings about XP, and however justified you believe them to be, it's not worth having a heart attack over. Let other folks make other choices for their own reasons. Freedom!
As for MC's sig, I sort of sympathize; I often find myself rewriting some program that was cloned from another program, and in the rush to get it running, a lot of unneeded code from the "original" source code was left in. Or the programmer used a generic structure better suited to a much more complex program than the one she actually wrote. Either way, you can make the program much easier to read, understand, and debug by removing all that extra code.
Where MC takes his sig too far is when he decides to remove functionality just for the sake of removing code, as in his recent decision to remove working WE APIs from Basilisk. Sure, that too can make your program easier to read, understand, and debug; but it also makes your program less useful!