Putting my armchair therapist hat on, I'm surmising that the amount of "we should just move on" posts from various members speaks to just how much the Frost era disappointed people. When he was hired we felt like we really had the next up-and-coming coach. Excitement was so high, and people genuinely wanted him to succeed.
When he didn't, and eventually got fired, that hurt way more than Solich, Callahan, Pelini or Riley's firings. So much so that it's hard to even do a post-mortem on the Frost era for some people.