Thanks, that's actually a good point.

I knew there was an option to vouch for comments but just assumed I did not have enough Karma to do so. But another comment in this discussion mentioned the "hidden" flag button, which you only see if you click the comments timestamp.

And sure enough, the vouch button is just there. So the problem may just be that you have to know where to find it. Which I now do. And hopefully everyone who didn't and reads this now as well.