One. You say Saigon….
Really, it doesn’t matter what you call it. Saigon will always be “Saigon” to me, but I get that there’s a history, and I get that…. No. Seriously, fuck it: no city name should have five syllables! Vietnamese history is complex enough without adding three extra syllables.
Don’t get me wrong: I mean absolutely no disrespect, and I think Ho Chi Minh was an admirable man who deserves the recognition he … deserves. But five syllables—nuh-uh!
My sense is that you are not going to offend anyone by using either “Saigon” (Sài Gòn) or “Ho Chi Minh City” (Thành phố Hồ Chí Minh). Hell, half the buildings and businesses are called Saigon-something-or-other. The airport call-sign is still SGN, the river is still the Saigon River, it’s the Saigon Train Station, and so on.
Just use some sense. If your Củ Chi tunnels guide is clearly from the north, is standing next to one of the traps, and uses “Ho Chi Minh City,” then be nice and do the same.
If you’re going to lose nose skin over it, then you probably shouldn’t have come in the first place.