I think the people that think this is just about the simple joke aren't that familiar with KF and Colin in particular lol.
The fact is, this shit has been happening more and more (antagonistic attitude, hypocrisy, claiming to be a good guy but acting like a piece of shit, etc.) and it wasn't really the initial tweet that made him look like an asshole (although including that hashtag did him no favours) it was his follow-up tweet that was basically stomping the boot on anyone who might've been offended while they were down.
Thing is, Colin's apparent hardcore fans and the rest of the KF fans don't seem to be quite the same breed, but there's obviously an overlap. While his creepy, "Hail Colin" fanboys might enjoy his weird sense of humour, there are a lot of KF fans who might not.
Part of me wants to make an insensitive, unfunny joke about 9/11 on that day this year to Colin and see how he responds. But, I wouldn't sink that low. "Oh but that's different, he has a personal relation to that" - so? I wonder how many people follow Colin who recently had a female family member pass away or something?