Your theory is hogwash.

They are not removed from sexual relations except by their own belief. These are imaginary chains.

Marriage is not required to have a sexual relationship.

Most of these guys (incels) want sex without any of the responsibility. This is what excludes them from the reproductive cycle and makes them unappealing. i.e. they want sex on their terms with a disposable partner who should be grateful. They make blow up dolls for that. They want sex bareback but won’t take responsibility for preventing pregnancy or any resulting children, etc. They are verbally and physically abusive to potential partners. They’re often deadbeat and dead weight.

They’ve propagandized themselves with nonsense.

They say they hate women because women won’t have sex with them. In reality women won’t have sex with them because they hate women. Honestly, would you want to be tied to someone in a familial situation who hates you? There’s enough hate out there. Nobody wants more at home.