Are you asking me why doesn't it work, or are you asking why do I say it doesn't work? The latter is easy (read the paper I provided above); that's what the best available data tells us.
If you are asking why doesn't it work (some have hypothesized that it does), that's trickier (and probably impossible) to answer.
Well, since I said, "why do
you say," that is what I was asking. I could be wrong, but to my knowledge there has never been a study of ivermectin that wasn't designed to fail. Ivermectin is believed to prevent/slow viral replication. The study that was done early in the pandemic was conducted exclusively on hospitalized patients, in which the virus had already substantially replicated. It was designed to fail, because if it worked, it would prevent an EUA from being implemented for a non-approved pharmaceutical.
If we look at the Uttar Pradesh example in India, they dispersed ivermectin to every person b/c it is cheap and at the first sign of any symptom or known contact, they took the medication. The results were staggeringly positive. IDK if it works, but I don't think anyone can scientifically say it does not.
Is there a link to the actual report? This website shows some graphs but it isn't clear if these are graphs that ONS actually made or if "some internet guy" pulled the stats and made his own graphs (I suspect the latter but am willing to read more).
Respectfully UNC, here and in so many of your posts you suffer from the Appeal to Authority fallacy. Just because someone has a credential, doesn't mean they are accurate or even trustworthy. So much of what the govt told us was essential was proven false. Much of what "Some internet guy" with an ability to reason, was slandered over during the pandemic, turned out to be true...because it was the most logical and obvious.
WRT to the above, the CDC released data that showed negative efficacy of the vaccine 2 months after being administered. I'll point you to the work of UK Cardiologis,t Dr Aseem Malhotra. After gaining notoriety blowing the lid on the overuse and side effects of statins, he has been vocal on the heart issues caused by the CV-19 virus and vaccine.
If you're really willing to read/listen here is a substantive conversation on the topic with Dr Malhotra