1. It's designed so people don't get their feelings hurt by having someone call them that, but in reality, it's extremely rare for a person to be called that.
2. There are plenty of other synonyms that are just as bad: "Moron", "Nincompoop", "Nitwit", "Dunderwhelp", "Gongoozler", "Micrencephalus", or "Gink".
3. Everyone knows that "Cool Dude" is just the filter. (Comparison: a cool dude [non-filter] vs. an cool dude [filter].)
4. Every BZP member knows what it means and have heard it in the real world before, undoubtedly countless times.
In my opinion, and based on the reasons above, I suggest that the administration remove the "cool dude" filter, and punish members when they insult other members or set designers, and not when they use that word to describe themselves. What's so bad about saying that you're a "cool dude"?