All things considered, I think this was pretty gentle. Heck, I've seen Trump fire people right on TV -- totally blind-siding them. Just looking them right in the eye, jabbing his hand out and saying, "You're Fired!". So, really, Comey got off easy.
Comical comey was in communist california when rudely interrupted mid speech and informed of his termination.
Those who are upset at his abrupt firing fear he had no opportunity to remove damaging evidence. See: prolific memos.