Neither change has any technical reason. The only reason why either name change was desired is because some contributors were upset by the names.
Whereas the “master” thing was transparent linguistic nonsense and a strictly-US cultural thing that a few people foisted on the rest of the world because they decided to get offended on behalf of a hypothetical group.
Thankfully the actual code remained the same (because only engineers look at it).
Indeed, neither has any technical reason.
I suppose you're right that both changes have a purpose -- one could feasibly convince a company to contribute Linux drivers (a net win for everyone), and the other is a constant annoyance which wastes everyone's time (is this project using `main`, or `master` -- you never know, so have fun getting it wrong all the time) just to allow certain groups of people/corporations to virtue signal**.
** -- If "master" is such a naughty word then where are all of the people getting offended by e.g. "Mastercard", "Ticketmaster", "Master Lock", "MasterBrand", and many other company/product names, and why those names aren't getting changed? Why there isn't any outrage about them? My point here is not to engage in whataboutism, but just to point out that the word isn't actually offensive when used in a non-offensive manner, and virtually no one is actually genuinely upset about it.
BTW, every country had its expansionist and genocidal and slavery moments (I'm from Italy, think about the Roman expansion inside Italy, then the empire or our colonial wars 100 years ago.) The USA is one of the most recent examples. It takes time and I understand that master vs main is important inside the country.
The issue of Wacom branding is different because it's a business dynamic and businesses don't want to work for competitors no matter the country, no matter the history. They can work together or an equal footing. So rename to libtablet or whatever.
In recent memory, you see this in response to last decade's trend of white people wearing Native American headdresses (particular to certain remaining groups of indigenous people in North America) at fashion shows and public events. This was practically the definition of cultural appropriation; in the cultures which display headdresses, one must earn the right to do so, and here you had the descendants of those who committed actual genocide wearing these symbols without even an attempt to understand their significance.
This is in a country that not only practiced genocide, it stole the children of native peoples, ostensibly to educate them to European norms, to cut them off from their hereditary culture; including their language and clothing. It's also a country that continues to ignore its own treaties with indigenous nations and erase their history through "termination" (the policy of un-recognizing individual tribes to eliminate their status).
So maybe it's popular here because this country is particularly terrible at appropriating culture. There's a ton of nuance you might miss if you don't live here and talk to people.