My knee-jerk reaction is “please dear god no”, and that’s not even getting into how non-person entities are elevated to the level of “social” interaction!
We’re not a business directory and we do not need to catalogue every advertising channel that a business might be using. If their social media presence can be used to contact them (hence contact:*) then I can just about tolerate it, but if we’re just recording their social media presence so that you can, you know, become a “follower” or whatever the term on the chosen platform is, then I don’t see why we should endeavour to become an accomplice in their marketing.
I can already see people writing bots to check whether the given platforms are still updated and automatically delete social:* tags, while at the same time scraping webpages to find new “follow us on blurble” links to automatically update OSM and I ask, why? Why does OpenStreetMap have to carefully map and follow every step that a company’s marketing division takes? Does it make us a better map?
Finally, if you want to ignore this whole screed, then at least fix the problem with giving major proprietary players name recognition (“social:x”) while relegating others to a generic “social:federated” (where apparently by this design you can only ever participate in one protocol world and never in two).