Short opinion.
I think that the reason people treat blocking (on social media) as this Horrible Unforgivable Crime is that to them, social media feels like real life; and in real life, Shunning and Ostracism are genuinely punishments for horrible crimes.
But the Internet is not real life.
My half-baked hypothesis is that people think this way because young adults right now had their formative years during COVID, when things forced us online much more than even the most dysfunctional people, and it exacerbated and accelerated a lot of already-bad social trends.
Emilybook 