i am not calling into question 72 hours (etc) because I don't want to dragged down into arguments that I am NOT trying to make but I do find the "take it and run with it to make blanket statements approach without qualification" a bit troubling.
for example:
most things that enter your body are no longer present in their constituent form 72 hours later. that doesn't mean that everything within that extensive range of substances cannot be dangerous and/or have side-effects, sometimes even side-effects that remain unresolved. just because something is broken down within your body within 72 hours (and hence no longer remains) it doesn't mean ipso-facto that that thing has not had nor has engendered directly or indirectly nor will so engender a negative side-effect.
we are dealing with a new frontier.
consider similar discussions with Curie/radiation back then before we better understood radiation: "it is in a sealed chamber so how can it hurt you"? would have been one such understandable line of reasoning back then.
even the corona virus itself (once no longer detectable in the body) has demonstrated the ability to leave behind negative effects which are will-o-the-wisp nebulous in form, the breadth of which is still being studied and expanded upon and for which the root causes remain largely a mystery.
there has to be room on here to separate the discussion of the science from the rabid "anti-vaxxers".
it is possible to simultaneously think that the vaccines are doing good (so far) without unquestioningly accepting all and sundry regarding them without critical, and sometimes very critical, critical thought [sci.].
that is all.
so I am willing to accept 72 hours as formulated in the arguments presented here but for me personally there are caveats.