Well, the title is messed up... Anyways, here is the point:
The "check mark" is only for moderators and adims to use. I think that normal users (and those who arn't normal) should be able to use them too! (To delete the comments.)
I thought to myself "with a title with that many exclamation marks, it's gotta be spam!" but before I actually say that, exactly what are you getting at?
I think the tool is hard to implement so that it only works on your profile. Although the trash can thing is implemented in that way, so I'm just not sure. This has been brought up and I know its under consideration. At one time (and it still might be like this) you could get the check mark box when you went to "view all comments" but then you couldn't delete all the checked comments so it was pretty asinine. We'll figure it all out though.