Definitely a viscious move by Snape (one would expect anything else?) but if it does break down the barriers both have put up and they become a couple, I could see them offering a very public "thank you" to PRofessor Snape for his "kind assistance". The resulting grinding of teeth should be audible from the Great Hall to the dungeons.
Author's response
I certainly wouldn't expect anything less from Snape. He takes every opportunity to humiliate and insult the Gryffindors during class, particularly Harry and Neville. There's no way Snape could pass up an opportunity like that.
You're right, though; Snape's actions may have humiliated Harry in the short term, but could have long term repercussions that Snape will be none too pleased about.