Here's my simple criteria.
I'm on Twitter/X, but none of the other social media sites they list (I mean, I'm on LinkedIn, but not in any sort of regular way). So their reach to me personally is diminished. Obviously I'll still go on their website if I want to keep up with their activities and I'll probably still hear relevant news about them though.
It seems to me that you realized at the end that "their reach to [you] personally is [absolutely not] diminished".