It's NOT dangerous if you don't install cr@p / cracked DEB's / cracked IPA's.
Yeah, right. Convince yourself all day long, why not. The point is, if you have a JB device and install something like WireLurker, you will be in much worse shape than on a non-JB device. Fact.
If you JB and don't get regular security updates, you are also more at risk. Fact.
But why not put your fingers in your ears and go La-La-La. I'm happy for you if you want to play with your device and rummage around. Just don't try to convince me it's less risky than having a non-JB phone.