US American science organisations are quite adamant that for them, it is America first. Stupidity has its place and these days the United States has a lot of it particularly as those same science organisations expect people from the rest of the world to accept "pre-eminence" of the USA.
There may be good reasons to be a member of these organisations but from my perspective, it is one thing to be with stupid, it is another to have these organisations argue their case on "your" behalf. So when you are a scientist, chances are that we already know you at Wikidata. We may even know about your science, your co-authors, your memberships.
Take for instance Prof Lise Korsten, she is probably South African, this is her Scholia. She has many co-authors and for some we do not know their gender and for most we do not know their nationality. We do not know if she is a member of any science organisation and we do not know that for her co-authors either. So you may add your professional memberships at Wikidata, your nationality and when you do know the nationality of your co-authors, you may add that as well.
In this way we make obvious to US American stupid that science is global.