I just found out about this video now through a Norwegian news article. It says that both Hollaback and the actress in the video have been receiving death threats.
Browsing the frontpage of /r/mensrights right now my general impression is that most of you guys here didn't like the video. (Not saying anyone here has been threatening anyone, just pointing out that many REALLY didn't like the video.)

I should add that though I'm not really a Mens Rights Activist, I'm at least a sympathizer. Still, watching the video, it seems like they have a point. I don't think what those cat-calling guys are doing is okay. I wouldn't like it as a dude. It doesn't matter that it's meant as a compliment.
Imo, if you like a girl, approach her respectfully and talk to her. If she obviously don't like, or wants, the attention, just let her be. Don't be butthurt. If you really want to find a girl, why don't you hit on a girl in an appropriate setting?

The video has been criticized for the white/non-white ratio, but even if it's accurate and the problem is mostly the non-whites, that is still a problem, right?

If girls get cat-called as much as the video suggests, I'd say it's a problem. If it's somehow not accurate, and cat-calling just happens rarely, once in a while, I think the girls should..