It's like "literally" in English has _changed_ its meaning. Yeah of course it originally meant non-figuratively, but it is clear to all that value language as a medium of communication (rather than a measure of intellectual status) that it now has another meaning as an intensifier.
The second part could be indicative of this being usage only acceptable for 'insiders' to employ, and the first part could mean but does not have to mean that outsiders / speakers of other languages / in other countries could and should use those very words. For example, in an American context one often hears "this country" to mean the USA, but that cannot be transported into contexts based outside the USA. Similarly, there's 우리나라 /uri nara/ lit. 'our country' > "Korea" in Korean but you wouldn't say "I'm flying to Urinara" or "I'm flying to Our Country" when you're about to board a plane to Seoul. In Japanese and Taiwan, the Japanese language and the Chinese language are often referred to as 國語 lit. 'national language' > "Japanese" or "Chinese" (depending on the language used). Of course you can't normally say "我不會講國語" in Chinese to mean "I don't speak Japanese" except when the context is clear and the listener can be expected that 國語 may mean Japanese in Japanese.
So Indonesians using "bahasa" in Indonesian doesn't necessarily license using that word in English.
I didn't get your point about "this country". The only thing I know is how it's inappropriate outside the USA, or in a global context, to use America to mean the USA, as of course the rest of the Americas also exist.
Let's say you don't speak German but keep hearing Germany referred to as "Vaterland" in the media. You might deduce that the word "Vaterland" is synonymous with Germany, and start using it yourself to refer to the country, but that would be wrong, because the word (without additional context) simply means "homeland", typically the speaker's homeland, whatever country that is.
Besides, the original commenter denied it’s used at all. Gp implies otherwise.
Broadly speaking, this whole business of trying to “own” words on an identity basis is poisonous, corrosive and an abuse of the tool of language.
Neither person in the discussion above claimed bahasa means “our language”. The positions were “bahasa=language(generic)” vs “bahasa=also colloquially used to mean Indonesian”.
It was your assertion/conjecture that it actually means “our language”. The (seemingly) native speaker posting the original comment did not make a similar claim.
"Bahasa" literally just means "language", the Indonesian language doesn't have eponyms, so to say "He is Australian" you have to include the noun "person", so "Dia orang Australia" (Sound familiar? "orang utan" means "jungle person"). Same deal with language/bahasa.
People saying "I speak Bahasa" sounds to me like people saying "I speak Sprache" to say they know German or "I speak langue" for French. It's eye-rollingly obnoxious.