The guy is very disingenuous in his arguments, plus notice how he overwhelmingly focused on male sexuality.

There is a clear pattern in male heterosexual behaviour (both in humans and other animals) where if they are denied sexual mates (by using consent, coerced or rape), then they will go with the "next best thing". And this 'next best thing' behaviour has got absolutely nothing to do with bisexuality.

You might remember that "gay ram" scientific study on sheep. Here they got a number of rams and then either forced them to have sex with other rams, forced them to have sex with ewes or gave them free choice. They found that one of the rams would only mate with other rams and this behaviour contradicted the behaviour of the rest of the rams. The other rams would mate with ewes (and given a choice would always go with the ewes), but when they were denied sexual mates with the ewes and provided other rams instead, the rams would mate with them 'as the next best thing'. If a ram in this study was bisexual, then you would expect it to try and mate with a mixture of rams and ewes if given free choice.

We can see it in humans with prison sex or when 12-year-old heterosexual boys engage in same-sex sexual experimentation because they lack the social and mental maturity required to have a girlfriend or because are stuck in a British boarding school.

The biggest problem is that this 'next best thing' response can become quite pedophilic. And if a society has a considerable amount of sex segregation that stops men having contact with woman and young girls, but still allows contact with boys, then heterosexual men in that society will start abusing young boys as the 'next best thing'. This is the type of behaviour that was in Ancient Greece or we saw in Afghanistan between 2001 and 2021 (read the wikileak cables on the matter).

Interestingly the author mentions behaviour on sailing ships in the age of sail, yet fails to mention that the sexual targets of the men on these ships was not towards other adult men but rather towards "powder monkeys" and younger sailors who were in fact child soldiers.

The reality is that this 'next best thing' behaviour (up until the last 100 years or so), has always been seen as heteronormative behaviour that did not contradict the social expectations of male behaviour, un-like homosexuality.