Wow, there is someone I can relate to on
I couldn't agree more with getting the first two points out of the way in an interview. Regardless of intellect, exposure, industry or experience, who wants to work with someone you're to all hate on a team? Team mental health far outweighs having that on your team any day IMHO.
Secondly, I had a similar experience in a job interview where I was asked to write out map reduce in pure python program structure (yes, that means including __name__ == '__main__' with full passable arguments, on a white board). I said almost as similar to you, "I can do it, but I'm sure to flub a few things here that my brains relies on with my IDE, not to mention, I'd just use the built-ins map() and reduce() vs. re-inventing the wheel and sacrificing efficiency in my algorithm."
I wasn't really offended or turned-off by the idea, sometimes I just think it's if you can talk-the-talk, can I figure out that you can even sort-of walk-the-walk and not just buzz-phrase repeating and 2 months into the job, you can't do it? But I think most of these people fall into that hard-on egotistical I-know-more-than-you shit and do me, that's like seeing who's dad could win in a fight in 3rd grade. I'm past it in a professional environment when everyone can bring shit to the table.