Okay, a little background is perhaps in order.
They are trapped inside an impenetrable force field on an island which is 2 miles long and 800 feet wide (IE, fucking tiny) with about 10,000 people living on it. Inside the force field, their powers do not work - even She-Hulk was depowered (Oh, but Carol still has hers, mostly). Their male friends can't come in and help them. (Amazing!)
They share this island with Mahkizmo, whose stated purpose it is to turn them into his slaves.
Mahkizmo is from an alternate future Earth which no longer exists as such, so he is the final remnant of it; on this Earth, all that mattered was power; weak men were killed. women were slaves by default and he, Mahkizmo, ruled over it all, because he has nuclear powers.
Mahkizmo is not very intelligent, and has absolutely nothing we would describe as ethics. He views and treats women as rape cattle. Add to this strength approaching Hulk levels and you have a fairly horrific combination.
Jennifer knows this, because she met him once before when his plan involved murdering all women on the planet in the present, to teach the women of his (altered) future an object lesson.
Back then, she was She-Hulk and could face him on equal footing. To face this psychotic sociopath now would be a nightmare to any sane person, but she thinks it is funny their friends can't come help them.