I skimmed the report, but do you think that people who work on this all the time would ignore the obvious? The joy of science is that others soon point out if you mess up. I've been listening to a few podcasts that discuss it. One mentioned that Italy had a much higher rate of death amongst known cases, but they think that is down to lots being missed. Discrepancies like that stick out. There are issues with how much some governments are covering up the facts, but having this happen in multiple countries gives us some basis to estimate rates of spread.
I am not an expert on scientific papers, but I expect they are written with some assumptions about who will read them. Those in the field will know all about the uncertainties. Maybe it's like not having to explain who Batman is in every comic ;)
It would be great if an epidemiologist would see your post and respond, but I'm not sure we have many on Steem (or will have on Hive for now).
RE: Garbage in Garbage out... the report from the Imerial College that has resulted in everything shutting down