Yes, the new anti-amyloids are not a revolutionary therapy. But they do have a small but definite effect on disease-progression. (something which in a highly noisy indication like Alzheimer's may actually mean a lot more to the patients than it seems by looking at the data. E.g. donepezil and memantine have very modest effects too, but patients and caregivers are still surprisingly positive about them).
And since these were developed using different methods and epitopes, it does not make sense to pool them together when doing a comparison. It's obvious that if you combine modestly beneficial compounds and compounds with zero beneficial effect then the mean effect will be worse than the modestly beneficial compounds.
And when you do so just because they were aimed at the same molecular target, not even considering if anyone claims that the old, unapproved antibody-therapies, with no positive studies to support them, have any effect, what you are doing is somewhere between extreme ignorance and deception.