I love random crits in TF2. Honestly one of the best parts of the game. I think - and this is a REALLY big think, not based on any evidence - that whether or not you're okay with random crits depends on your perspective coming in to the game.
If your perspective is: "I want to play a competitive class based game in which skill, knowledge, and teamwork are the only determining factors for who succeeds," then random crits don't seem to make any sense.
If your perspective is: "I want to play a funny cartoon shooter where funny cartoon men shoot funny cartoon guns at each other and lots of funny cartoon antics happen constantly" then I would argue random crits are not just okay, but actually required.
The issue arises that TF2 is half of each at the same time and it's really difficult to force it to be just one of those without significant alterations. Therefor, people who approach the game who enjoy both perspectives on their own merit usually have the most fun over a long period of time.