Especially when he had to answer in the affirmative, that there is indeed a conflict of interest, but it's a really tiny one that hardly anyone would be bothered by.
Google has a well known, and well documented history of donating to open source projects to get their own products added as defaults. Combine with a for-profit company (RedHat) who does not disclose all of their financials (and that’s their prerogative), and it’s a perfectly reasonable question to ask.
The original question was stupid. We all get that. We’ve all suffered that on occasions at work. But that doesn’t justify his grossly unprofessional response.
Especially when he had to answer in the affirmative, that there is indeed a conflict of interest, but it's a really tiny one that hardly anyone would be bothered by.