If you're a software vendor and a researcher comes along a claims there's a problem with one of your offerings, and you (the vendor) think there is not, you issue a public statement to the contrary. That's fair.
However, if the researcher persists and manages to prove his or her case to you, what do you do?
If you're Microsoft, you own up to the problem, and thank the researcher for making you understand.
That sure looks like the right way to do things to me. At least, the drama will probably only last about a week.