I went to Vietnam a couple times. If you hang out downtown in the city, you might get a random Jehovah's Witness or Seventh Day Adventist* try to chat you up. "Oh, we can't do missionary work out in the open, so we just do one-on-one conversations like this". Despite the lack of "Jesus saves, die sinner" signs in Hanoi, you can definitely find Catholic and Protestant churches in Vietnam.
The Western press likes to piss and moan about settler nation missionaries that go, without proper visas mind you, to spread their Western versions of Christianity to the DPRK, only to get deported. So am I allowed to enter a white people country without a visa to stir up trouble and expect no consequences???
I'm the furthest thing from an expert on Myanmar. I get everything I know from Burmese friends. But if you look into the minority people situation, many of them are being heavily proselytised by the worst of the Amerikan type. I don't want the Pat Robertson's the world anywhere near struggling people.
*I'm definitely not saying that JWs and SDAs are anywhere near the worst as Christian sects go.
I'm not sure if it's necessarily just Orientalism. Most posters here tend to be Western, white and have probably had some kind of Christianity-adjacent upbringing so they're understandably wary about going off about non-Western religions they're not that familiar with. I don't think many people here would be comfortable declaring that we need to abolish Islam and Judaism either. They just don't want to come across like a Western chauvinist
I think it's just "grass is greener" thinking.