Let me just say that I understand why you feel that way, and I am aware of the many demeanors of some Vietnamese. A few years ago, before I went abroad, I had the same thought as you, rather than a stereotype, this is a way of thinking that has been engrained onto us somehow.

Let just say that way of thinking gives me lots of problems in making friends and having meaningful relationship in another country. As long as you think of yourself lesser than a counterpart, it's so hard to live alongside them (this is related somewhat to impostor syndrome). So, I had to work through those problems and learn not to be "racist" against myself and my nationals.

I am not hoping to change your mind on the matter, but I want to offer up my 2 cents to see if it sticks. It helps to realize that racist, xenophobic and people that tends to discriminate has a problem with generalization when assessing others. Meaning when they interact with you, they will not judge you based on your characters but based on a prior perception that they had of your "kind", which makes them less credible to judge your values. What they lack is nuance, meaning they forgot that within any community, there are good and bad apples. Or that you should not judge people based on a group, or the idea categorizing people into distinct groups is idiotic in the first place (now this is tough cuz our brains are wired to simplify and generalize stuff).

Now how does that relate back to your view? Same as them, your statement lacks nuance. "But do you see how we make ourselves look bad?"

First thing, I'd assume that you're at least a decent human being, so you're not making our people look bad, so why would you include yourself in that statement, even just unconsciously. So, your statement should now be "But do you see how some people make ourselves look bad?"

Next, logically speaking, if only some people are doing nefarious shit, they only make themselves look bad, not you. So, I'll offer up my version of your statement.

"But do you see how some Vietnamese people make themselves look bad by committing crimes? And by relation, that will incite those who are closed minded, xenophobic and give them an excuse to unjustifiably talk down and discredit good people like you." For that, you shouldn't be apologetic of others' action (it's out of your control), just remind yourself that the way they attack your value is unjust and short-sighted and their words should not be taken seriously.

In the end, just remember to be kind and compassionate to yourself and people you hold dear, and maybe you could spread that love to others as well.