The reason these areas were created, and the reason a lot of campuses still maintain them, is that in most cases the "speech" we're talking about is recruiting/issue advocacy by a student organization that wants to set up tables with a staff of a few people - at the smallest. Sometimes we're talking about something bigger, like a jump castle, a blood donations bus, or even - in one memorable instance - a giant plyboard cube that students were encouraged to graffiti. Really what we're talking about is a logistics issue, not some speech fascism on the part of the college. Trust me, other forms of organized speech - flyering especially - aren't restricted at all.
Hell, I remember more than a few war protests that began AND ended outside the "free speech area".