Stupid is the only way I can describe a prey animal that runs into a predator's mouth. I've always thought they must feed a lot of predators in the wild.
They're native to to North Africa and their instincts are geared for what's there. Mine are winning the "not being eaten by a predator" contest with my chickens: 3:7 so far.
I've seen my guineas use pack tactics to drive off hawks. I've also noticed they've learned the distress sounds of my chickens and the "goon squad" often shows up if the chickens sound like the they're in trouble. They'eve even backed up my roosters when they go into protector mode.
When they were facing off with a coyote that was trying to get through the fence, I didn't stand by idly and watch them get killed (which is pretty stupid if you ask me). I got one of my shotguns and started shooting.
Didn't kill the bastard (those things are FAST) but the guineas cleared out into cover while the gun-play was going on. They walked up to me when the shooting was done and when I got done with the head count I made the herding gesture I trained them to respond to and they silently filed back towards their coop.
That was the second time they flushed out a predator and kept their cool when the shooting started.
Other times I've went to deal with predators and had a couple of my guineas act as backup: they'd get into formation with me, one on either side, and start screaming their heads off.
Yeah, sometimes they'll jump at something they have no hope of handling. But guineas are hard-wired to preserve their flock at all costs. It's not stupid, it's selfless.
Honestly, I've had dogs that weren't as good at guarding my property as guineas. Fun fact: in the middle ages they used to stock castle moats with geese to act as watch-animals for the castle. I think the only reason they used geese is because guinea fowl HATE getting wet.