It's pretty obvious where that reaction is coming from.
As recently as last year Microsoft was singing the praises of being able to kinda-sorta-use desktop software on a tablet and pushing the notion that things without desktop operating systems were 'consumption' devices, at best.
So, yes, their sudden reversal on what people want in a tablet is worth noting and easily justifies the same kind of quips and barbs that people lob at Apple over Jobs' similar reversals [1].
And it's pretty easy to be ahead of the curve on blending mobile and desktop operating systems when Microsoft is the only party who sees a problem to be solved in the first place. [2]
Because this entire concept -- that people want both -- comes apart at the seams about a month after you've owned an Apple or Android tablet. [3]
Simply: there's no user-facing problem being solved here.
People use tablets for what they're great at and desktop PCs for what they're great at. And no-one who's ever put their tablet down to use their laptop is looking at that Microsoft Surface tablet and saying "this will mean I don't have to put the tablet down for these tasks anymore". [4]
Microsoft is attempting to solve it's own problem with this blending concept and the degree to which this tablet succeeds, is going to strongly track the degree to which Windows stays out of the Metro experience [5].
[1] "No-one wants a widget."
(Smash cut to 18 months later)
"Introducing Apple's new iWidget!"
[2] That Windows is irrelevant in a growing computing market.
[3] And I say that as someone who has been pro-tablet for a decade and only grudgingly gave Apple's "big iPod" approach a chance.
[4] At best, the typing-heavy market is saying "I wonder how long it will take someone to make an iPad keyboard case that slick."
[5] Metro is a unique, interesting and a refreshing change from Apple's icon grid. And I've heard far more praise for it from the design folks that get written off as Apple fanboys, than I have from the Windows crowd who generally echoed Microsoft's 'consumption' FUD.