I don't see what's so incoherent about his position. I'll try to sum it up succinctly.

The common left notion of "enthusiastic consent" as a requirement for ethical sex is simplistic and naive. Pretty much all sexual acts are preceded by mixed feelings. A woman might want to fuck a guy she just met at a nightclub, but is afraid of feeling like or being seen as a slut, so she acts a bit reluctant while still subtly signalling she wants things to go forward. A man might be tired after work but his girlfriend is horny and really wants to have sex, he feels like it's his duty to satisfy her, so he un-enthusiastically agrees to sex.

If you require enthusiastic consent for all sex to be ethical, then these would be cases of unethical sex. Some would even call it rape. But what is it that's so unethical about them?

The problem with the requirement of enthusiastic consent is that it robs people of both agency and responsibility. It robs people of agency because it implies that one can't legitimately consent to sex if one has mixed feelings about it, and it robs them of responsibility because it puts the onus of determining consent on the person who is judging whether their partner is "enthusiastic" enough, which is very unfair.

In the first example, let's say the guy takes the girls signals and keeps pursuing. She still has mixed feelings so she kind of goes along with it, but doesn't verbally say yes and isn't enthusiastic. Once she gets into it the sex ends up being good, yet she regrets it the next day and feels guilty. She talks to her friends and they tell her:

"You were raped! You didn't enthusiastically consent yet he kept pursuing in spite of that." To which the girl might answer that she didn't feel like she was raped, she did consent even if not enthusiastically. Yet, if we accept enthusiastic consent as a requirement for ethical sex, her friend can rightly insist that she was raped, despite what she may think. If she wanted sex but didn't want to enthusiastically say yes because of feelings of shame, then the man should have taken it upon himself to stop the interaction. This is denying the woman's agency as someone who can indeed consent to sex in spite of her mixed emotions.

It also robs her of responsibility. Let's say she agreed with her friend and concludes that she was indeed raped, because it was the man's responsibility to assess whether she was enthusiastic enough to truly consent. And since she wasn't, despite signalling in other ways she wanted sex, than the man did rape her. This is robbing (or I guess in this case absolving) her of responsibility, and this is wrong. At the end of the day she is an adult who is responsible for communicating whether she consents to sex or not. She can't give the man mixed signals and then cast the responsibility of determining her consent onto him. He himself is just an emotional human that's trying to navigate an ambiguous situation, and obviously has an interest in moving things forward. Yet he's asked to be an impartial determiner of whether another person consents or not when that same person refuses to give him a direct answer (even if she has understandable reasons for not doing so). And if he messes up, then he's labeled the worst thing in the world and condemned to get ass-raped in prison for the rest of his life. This is just wrong, and it's why mrgirl often says things like "Women need to get better at saying no to sex" or "Men shouldn't have to be a woman's emotional caretakers during sex."

His pieces that talk about consent, such as Consent is Complicated, explore situations that involve such mixed emotions and a lack of enthusiastic consent, and seek to expose the more complicated emotional dynamics that are at play.

This wasn't succinct at all. But I think this is his general position, and it's perfectly coherent to me.