Am I reading this wrong? It looks to me like the author is condemning the idea that everyone should be pansexual. He spends a lot of time outlining the 'logic' behind forced pansexuality before dismantling it and calling it absurd. The highlighted bit reads more to me like he's repeating how wokesters think for the sake of argument before calling it 'the worst kind of social engineering' in the next paragraph. He even ends the article like this.

But my general instinct is that I’m loathe to tell people whom they should and shouldn’t find attractive. Though it’s prima facie plausible that casting your net wider than your current sexual preferences will make it easier to find someone to love, I think what’s likelier to happen is that you’ll waste a lot of time trying to be with people whom you end up not that happy with. It’s difficult enough to find a good life-partner. We shouldn’t make it harder.

It doesn't look like he's saying pansexuality is obligatory. He's agreeing that trying to make it obligatory is ridiculous.