What is the basis for writing them off while accepting the claims of others? Strong political bias.

I respectfully disagree. I can write off someone's claims without it being based on political bias. Instead, I examine the plausibility of the arguments made by each side, as I discussed previously. To avoid forcing you to re-read my earlier responses in depth, I will re-iterate the substance below:

I am not sure that Ivermectin doesn't work. But having read the analysis of the trials in the link I shared, I was persuaded that randomized blind trials are likely to be significantly less biased than other trials. This didn't seem to be some new idea, but standard thinking, and the argument makes sense to me.

I have no bias against Ivermectin, in fact, I would be very happy to see convincing evidence that it does work.
But what is clear to me based on my reading of their writings, is that most of the people pushing Ivermectin are, in fact incredibly biased, and contrariwise, I haven't seen any evidence that the WHO is particularly biased on this issue, nor can I think of a plausible reason for such bias (no, I don't think it is likely that the WHO is being paid of by vaccine companies).

So, weighing the plausibility of the arguments made by each side and the relative bias of the presenters of those arguments, my conclusion is that Ivermectin more likely than not doesn't help as much as it being promoted to help (I wouldn't be surprised at all if it helps some), at least not in the doses that humans can tolerate.

So I'm not arguing against someone taking Ivermectin as possibly it might help. But I think it is extremely foolish for anyone to pin their health hopes on a belief in a drug where the evidence is still cloudy, when there is clear evidence that vaccines do work. That's the mistake I am warning against. You can take Ivermectin if you get covid, and maybe it will help, but it is too late to get help from a vaccine at that point if it doesn't. And the evidence for vaccine effectiveness against covid is very compelling.

Nothing is so cut and dry I think as this thing is the answer, this thing is bogus.

As I hope I have made clear at this point, that is not what I'm doing, at this moment. But I disagree with the above assertion: with further study, it is certainly possible to come to such a conclusion: this is science and things can be proven with time and sufficient experimentation to all true scientific satisfaction. This is a basic premise of Western medicine, and it is a tenet I find supremely logical. Some things are the answer to some questions, and some are bogus. But I don't think we have reached that point on Ivermectin yet (although I suspect we will before too long, I just don't know what the answer will be with certainty yet).