Debunk away! There are few things more annoying in the fandom than shippers/theorists/crazy people presenting things that are simply not true as if they are valid arguments. Interpretation is wonderful and fun and adds much spicyness to the fangirly life, but only if people are not willfully, purposefully ignoring what the books actually say (or do not say).

I don't have any passionate interest in the love lives of the kiddies in the HP world, but I think "Ron and Hermione fight all the time" is right up there with "Sirius was a womanizer" on the list of Things That Aren't Meaningful In A Debate, Because You Just Made It Up, Stupid. :)