Syag > There are guidelines to determine if something falls under the halacha of being pikuach nefesh and there has been such a crazy misuse of this over the covid years.
I am relying on these psakim, for example:
R Meir Twersky suggesting that while in a regular medical case we should ask a doctor, in a case of new, uncertain, plague, we need to behave according to the most careful of multiple experts, and also more careful than politicians as we are always more careful about human lives than non-Jewish society in general.
R Heinemann: do not try to do anything that can be misconstrued as uncareful behavior so that Jewish community is not judged and then denied treatment by someone.
But you are right that estimation of the risk is somewhat subjective and some risky behaviors are accepted in society and Hashem protects simple folks who take small unnecessary risks. This, of course, does not apply to esteemed YWN posters who were exposed to facts (among other posts) and it does not mean that better behavior is not encouraged. Gemora warns us against drinking cups in pairs and walking between palm trees for a presumed danger. Surely, amoraim would not approve a clearly quantifiable danger.