Because there are lots of people that use Meta products as their only social media platforms, and the No Kings movement wants to reach out to those people as well. The Electronic Frontier Foundation has had multiple social media accounts on platforms they don’t really stand by for the same reason.

Lose, with only one ‘o’:
Verb. To stop having something you had before, with a negative connotation. To not have success at game or competition.
Dictionary entry: https://dictionary.cambridge.org/dictionary/english/lose

Loose, with two 'o’s:
Adjective. It can mean the oposite of either “tight”, “attached” or “controlled”. It can also be a verb, and in that case it means something similar to “let loose”.
Dictionary entry: https://dictionary.cambridge.org/dictionary/english/loose