I visit Barcelona quite often for work, but do try and visit the local area while I'm there and do 'touristy' things. I've had, on three separate occasions, groups of men harass and shout profanities at me, telling me to f- off back home, or calling me a filthy tourist; once going as far to follow me around jeering while I was taking photos, trying to intimidate me and forcing me back into the more populated areas.

I'm not surprised you don't see how anybody is harassing tourists; you're a local so you don't get harassed. That's doesn't mean it's not an issue.