Is the practice of eating dog meat in Vietnam morally acceptable?  

I think it is still considered "normal" there but it is worth noting that dog meat is not a poor man's meat like many assume. It is more expensive than pork and not as widely offered in restaurants. I have issues with it but I know it is not my place or culture to do anything about it. I just choose to go to places that don't offer it.

I think people are indifferent. Some don't like that people eat, others don't care. I think it comes down to what region of Vietnam it is these days. I personally would not eat dog, nor cat for the matter. I don't eat carnivores.  

I never came across it when I was in Vietnam and didn't even know it was a thing people ate. Maybe it is not as common now compared to 10 years ago? I know in China they eat both cat and dog which is frowned upon by most other countries. 

I don't like it. I don't like when people eat dogs or cats. I never knew it was a thing in Vietnam until reading this which means it must be a rare thing, right?

Still popular, especially in the North. Dog meat shops and restaurants are everywhere. I ate some once (the people who served it to me told me after I had eaten it); it is good, tasting somewhat like the tender beef you use to make a stew. 

I was offered it once. It was not the "entire" meal but a small portion, almost a sampler of sorts. I declined. I don't agree with it but I don't judge people who do eat it, especially when it is a part of the culture. 

You never know what you're eating at some restaurants!

Funny true story in Paris. When an old building was demolished, the workers found a well full of skeletons of cats. After research inquiry, it was found that, before, there was Chinese restaurant there.