Typically because of anger and lack of rational arguments, I assume.
Totally understandable. Accountability is very important. Concern is .. meh. If people have concern ask the FDA & CDC & Pfizer/Moderna. Get informed. If the answer from the FDA et al. is not satisfying, ask again, reach for the usual tools, FOIA, etc. Get the data for the clinical trials, check them. Get the data from VAERS, and so on. (Just with Ivermectin there's plenty of things to look at, get to the bottom, maybe even form an explanation of the data: https://astralcodexten.substack.com/p/ivermectin-much-more-t... ... and in the end it's possible to be still not 100% convinced.)
But "oh it's rushed, I'm concerned" or "it's experimental" is about as valid as "oh my head hurts, it's because of those damn Wifi towers / windmills / transmission lines!". Countrywide health/energy/communications policy should not be made because propaganda induced mass hysteria.
See also rock music and DnD and souls of kids.
Maybe the right question to ask is "why it takes so long otherwise?".
This phrase is often used to malign those with a different understanding or opinion. Most people who question the efficacy and safety profile of the experimental Covid vaccines are neither anti vaccine nor nutjobs.
> Oh and baby bottom redness is not infectious and as far as we know did not kill anyone.
The talc powder lawsuits are because it is suspected or causing cancer. Yes, they made something with long term side effects. Which is why some are concerned about the rushed implementation of Covid vaccine mandates.