since when does anyone read the Terms and Conditions.
I always skim the TaC of a new site, and then use a day or two to get to know the site, how to act and find out if there are any special rules to remember.
On whether it is unfair to delete short comments: If you are just saying how good you think a game is, you can do that just as easily by rating it. It does the same thing: Show people you enjoyed the game, or for that matter, didn't enjoy it. Writing "awesome" or "bad game" or "lol" just unnecessary and does not add new information to the information you already gave, the rating.
Which is why the comments are for longer, more constructive feedback. Stuff you cannot say via the ratings.
And, well, if you are going to doublefill it anyway, at least have the courtesy to make longer comments. While they are most likely useless*, you at least bother to follow the rules.
*see the "why" rule-of-thumb.