I think that asking overly hard technical questions is bad for reasons you said, but if an engineer gets offended over simple "implement linked list" or other basic exercise, something is wrong with that engineer. Either it is that he/she masks some lack of basic knowledge or he/she is too much of primadona. It is perfectly ok for interviewer to check on basic skills, since all interviewer goes by is what you say about yourself.

But, if I had enough social skills to tone down "geeking" withing 10 minutes of interview with stranger, you would not hire me? That is just side note through. The older I am, the less I like to frame myself as "geek", there are some cultural aspects I have grown to dislike. A lot of "geekinesss" is actually trying to be cool rather then anything else.