Being skeptical is not the same as dismissing the entire connection as “bunk”. Derek is a much respected voice in the field. I actually agree with his take, and he is spot on with the quote you provided.

What makes lecanemab different? Compared to other drugs in its class that we’ve seen thus far, it has much higher affinity for amyloid fibrils and soluble oligomers than plaques.

https://www.frontiersin.org/articles/10.3389/fnins.2022.848215/full