Commenting without voting really makes no sense.  I'm far too lazy.  It makes sense to me to vote but not comment (i.e. you enjoyed the post but really don't have anything of value to add).   But if you take the time to comment, it seems to me that you are doing yourself a disservice by not voting. There's a tiny bit of curation reward waiting for you.  And that vote button is right there.  I don't even need to scroll!!!

Unless.... they are doing it simply because they know that it ticks you off.   In that case, it's simply funny.