I can appreciate a little rough housing as a kind of foreplay or even during sex... but getting beaten up just for kicks? Huh? Am I missing something? Where's the fun in that?

I suppose like every other fetish (such as muscle/bodybuilding for example) you have to be into it to appreciate it. Apparently, enough people are into this pseudo wresting/schmoe sex scene to create a market for it. These wrestling sites and videos are common on the internet.

I guess it's just an extension of the professional wrestling people see on TV.