Is it genuinely offensive to be asked the complexity of bubble sort? If such a question causes you so much offense that you lash out involuntarily, then you have some serious personal problems to work out.
Offensive, no. Just trite and tedious.
And more fundamentally, simply not indicative of the high quality, (genuinely) cerebral environment the interview subject, back in the original article, is looking for.
Why be rude to the interviewer even if that is the case?
I get that it's generally better to be polite. But when the same kinds of tedious and disspiriting (and sometimes downright condescending, and/or simply time-wasting) behaviors come down the interviewing pipe, over and over again... I can understand the temptation to bypass decorum, and allow a gut-level, emotional response to surface.
Being as while we might generally prefer to keep things professional -- we're not potted plants, either.
If a few more people were genuinely afraid of being humiliated for blindly cargo culting google's hiring practices it might go out of fashion quicker.
At least, that's my hope. Which is why I usually tease people for doing this (yes, that upsets them).
I think you need to pause, take a step back, and consider who is actually making an ass out of themselves in that situation.
It's more effective when you're over-the-top polite when you set the trap with leading questions though.
Trolling gives me a bit of mild amusement in what is otherwise a dud investment of my time. The only people who seem to have a problem with that are people who have an exaggerated respect for authority figures (always unhealthy).
If, on the other hand, the interview process is obviously relevant to the job at hand and thorough I go out of my way to compliment the interviewer to their boss even if I know I failed.
(I should note that, as a consultant, nobody ever asks me to whiteboard some code for them, despite often committing into their own repos and doing work that is no less important to them as a company. Almost like the hoop jumping is just some power-move crap on the part of the interviewer.)
Politely leaving without saying anything doesn't improve the situation for anyone. These pop-quiz questions need to be stopped.
Tongue-in-cheek aside, of course passive-aggressive isn't the ideal path to improving interview processes. :P