On my iPad with iOS 4.3, I can't up vote or flag comments. Is this just me? Or can this get fixed?
You can, but you must
At least it has always worked for me that way on the iPhone, or as I like to call it, my iPad Mini. Voted for comments on iPhone many times using that technique.
(and you know about two finger scroll for scrolling divs, right?)
I believe, it's fixed now (I have no problem with IPad 2 iOS5). According to very similar Voting up comments no longer possible via ipad it's completed.