I’d be genuinely interested in an elaboration. Reading the article, the fundamental issue seems to be that he’s an idealist utilitarian who opposes racism and animal suffering in the wrong way?

The article concludes that

Of course, there are plenty of good reasons to become a vegetarian, to advocate for better treatment for animals, or to oppose factory farming.

But I genuinely haven’t seen such reasons which do not ultimately end up in some form of Singer’s argument that suffering implies moral value. Do you have a link exploring it further?