I hope this person is OK but that strikes me as unrealistic. Ageism is a real problem for software developers, but also that 15 years at MS could just as easily be viewed as a negative than a positive.
That 15 years of experience at one of the world's top software companies is seen is a negative disgusts me.
It seems disrespectful to judge an employee based on the negative perception of an entire company. For all the broken things within a company like Microsoft, I think it would be foolish to mark the company's talent pool as tainted.
Perhaps this reflects a subtler form of the fanboy-ism that exists in technology culture today. The sentiment is that companies we dislike must have incompetent employees. Competent employees would surely build a better product, right? Obviously this is naive.
Absolutely right, ageism plays into this as well. If you're hiring, keep in mind that, while fashionable, it is illegal to discriminate based on age. I wish this law was slightly easier to enforce.