Why don't they peacefully protest in the streets?

Autocratic dictator starts arming supporters, who are going out as militias to intimidate and suppress insurrection. Yes, militias can cut both ways; they can be baneful or helpful.

Anti-gun people would have you believe that the anti-regime protesters should just go out in the streets and peacefully protest. Yet, for some reason:

In Tripoli, most residents remained in their homes Saturday, terrified of bands of armed men running checkpoints and patrolling the city.

Libya is a gun control paradise. Libyan leaders have come out and said that "of course, the people have no arms." Of course, according to a small-arms control site, Libya's regime didn't restrict firearms at all. This site reports that almost a million firearms were in private hands and half a million in government hands, with no regulations other than requiring markings (serial numbers). Of course, I'm sure many of those million privately owned weapons were in the hands of regime sympathizers, and I'd be willing to bet that some other arms control measures were implemented, even if "unofficially."

Still, the asking price for an AK-type rifle is only $250 or so there apparently, so it isn't surprising that anti-regime insurgents managed to arm themselves fairly quickly. They know that peacefully protesting in the streets against a regime like Qaddafi's isn't a winning strategy.