Oh, I didn't know. I don't self-upvote unless I want my comment to go to the top so the author sees it, because I want their take on my idea or something. And of course to boost my posts in the site listings. It looks like that's enough to put me on that list, however.
And I'm not sure if the bot-makers live in third-world countries!
The ones I'm thinking of speak broken English, often have selfies for their avatars which show they are clearly Indian or Arabic, and have names typical of those regions. But of course there are Westerners who do this too. Maybe it's just confirmation bias, and I'm only remembering the ones that were funny to me because of their mangled Engrish.
Fair enough but let's not forget that we have many refugees and/or immigrants living in the West who can't speak proper English! :P
And furthermore, you might not recognize the ones with good English, because their bots are obsequious, but more subtly so. Like, "Ha!" on a post in "funny" is probably a good bet. Sometimes I want to write that because my voting power is low, but I have nothing to add to the conversation, and I just want the author to know I liked their joke. It's rough, yo.