Ah, I could be wrong, but I think "hide all posts" just makes his profile posts not appear in your newsfeed. It's a good feature if you're friends with some super-active person who has mass-added people (i.e. - they're posting stuff all the time, but if you don't click it within the first 2 minutes it has expired). What's nice about this feature is that you only prevents his posts from appearing on your newsfeed, but it doesn't stop you from being able to see his posts if you go to his profile.

The feature Raymond is thinking of is this one: What you'd want to do is click the "x" next to their request and choose "ignore all requests".

Of course, that will ignore ALL requests sent by him, not just the spam ones.