You are correct. He used a VPN for several US locations in the video. He then compared what content was shown in different regions of the US to see if everyone sees the same thing or if the content is radically different depending on where you are.
if so wouldn’t that just end up with the USA following strange semantics other countries don’t?
When it comes to renaming external locations like this that are used by multiple countries, I would imagine it would be a case of how wide the rename is adopted. If I had to take a guess, renaming the Gulf of Mexico or the Atlantic Ocean in more US-centric names isn’t as likely to catch on globally and will probably just result in confusion when people from different countries are referring to the same thing.
I’m from the US as well, and I can verify that very few average people use those types of messengers primarily. It is almost exclusively iMessage and SMS/MMS/RCS texts as the main form of messaging. I will admit that quite a few people will use the messaging features that are built into social media apps (like messaging in Snapchat, Facebook Messenger, etc). At least to me, it seems like those are moreso used for sending memes or messaging people you don’t interact with regularly and are still secondary to the other forms of messaging.
I check friends’ Snapchat stories from time to time, and Snapchat suggests public stories on the same page. I think Snapchat has the same sort of singular data point on me that “this account is likely a straight man”, because most of what they show me are sports clips, woman influencers in revealing clothing, and right-wing influencers talking about culture war stuff. I never view any of that sort of stuff, but it still shows up any time I try to check my friend’s stories. I guess I view public stories so infrequently that they just give me a default generic man feed.