He is just trying to publicly discredit the competition. If you actually think Microsoft is ignoring Android internally, then you are very mistaken. He was asked a question about it and answered it. His only realistic options were to do what he did and talk about it in a negative sense or politely refuse the question. What else would you expect him to say? He's not going to legitimize a competitors product, especiall…
For example, he could say, "We've had a look, and it certainly has its niche, but ultimately it's just another Google Labs experiment in Perpetual Beta. Anybody remember ___ or ___ or ___ (he names some Google Labs has-beens), experiments that didn't turn into anything?
We'll have more to say when they release a version with fewer bugs and rough corners in a year or two."
Then he smiles and shuts up, refusing to say exactly what the bugs and rough corners are. This is a lot more believable, and it positions the phone as an experiment. That would be close enough to the truth to raise some doubts. And even fans might be reminded to wait for a faster, cheaper, better version down the road, which would undermine their sales.
Or he could reposition the phone as being hard-to-use, which some of his market believes is the case about Linux. Or "incompatible." Or any of half a dozen reasonable quasi-objections that spread Uncertainty and Doubt. But a bald-faced dismissal runs smack against reality.