Good question. I'm not opposed to hiding them...but honestly, it's also good for users to have an idea of what is spam and what isn't. Seeing the locked topics sets a precedence for all of the spam stuff that we can't sit down and define.
Yep. At least, if that's the majority of the post. If they say stuff like "The hype train can't be stopped" and then have a lengthy post about which 2015 sets they like, then that's discussion. But if not, then it's definitely spam.