You have to look all the way to the right side of the page and up to click comment, then scan all the way back to the left side of the page to make the comment in the little box on the left. It's particular odd when there are a lot of replies, as your looking for a reply button that's not inline with the last post.
This is on a small 13" laptop screen, I imagine it's looks even more odd on a large desktop screen.
I think it's always been like this on the profile posts page, but less accentuated as the thread is further to the right, rather than aligned to the left side of the page.
I guess it's only a problem on fluid themes too, so probably more of a suggestion than a bug, to move these two buttons closer to the report button somehow...or have a comment/reply button at the bottom of the thread.