It is true; the PDF linked in the GC has to make a number of assumptions and is very obviously made from a point of bias (which does not invalidate its claims but warrants extra scrutiny).

Also it's comparing raw ICU admissions, but there are a number of really nasty adverse reactions that don't throw you in the ICU. The general "second shot syndrome" that something like half of people getting Pfizer/Moderna experience is a great example of that. Yeah it's not bad enough to send them to the ICU, but for many people COVID-19 would be literally asymptomatic or would be minimally symptomatic, whereas the second shot syndrome can be quite brutal.