Obtaining useful information in contexts or from people you find unpleasant is a handy skill.
For small N, finding something in an association list can be faster than finding the same thing in a hash table.
Naggum also could have run some quick bench marks and figured out at what size N hash tables become a better choice (depending on the nature of the keys, etc. etc.), in less time than he spent berating the intelligence of the questioner.
Only in edge cases like looking up a long string in an alist consisting of one short string he's right.
When I was working through the book (and I still am to some extent), it was basically beat into my brain that some algorithms with worse performance could perform better than faster algorithms for a small enough n.
Is it really that hard to say, "Complex algorithms have higher constant factors, so for small values of N, 'naive' ones can still be faster. When in doubt, measure." without chewing somebody out?
It's easy to deliberately overlook rudeness, but it still unconsciously colors a person's responses and thoughts, which could have a negative impact on the message.