He's more or less right, though that's not exactly a good thing. It's a rather defeatist attitude, which is understandable but again not good. I think most people are relatively decent, most of the time, and it's really a small but more visible minority that are more blatantly and noticeably racist or prejudiced in their interactions with others, making it feel like it's even more pervasive than it already is. So to say everyone is going to suspect everyone else of the worst until shown otherwise is just giving into the mentality of those few truly horrible people.
But, no joke, that could very easily be my white male privilege talking and everyone really is that shitty. There is also no shortage of people who unknowingly do, say or react in prejudiced ways without malicious intent but it still reinforces that world view and comes across that way to those on the receiving end, pretty much making it no different from purposeful malicious stuff. Our society is so hyper aware that everyone seems to be looking for things all the time, and there's plenty to pick up on, but I can also imagine there are a lot of perceived slights that are anything but. Which again makes me feel like this isn't the greatest attitude to have even if it is true in a lot of cases.
What's the end goal? Everyone feels shitty and self aware about everything they do and how everyone sees them until we reach some magical low point where everyone realizes we're all the same and we start treating each other like equals? Cause that doesn't seem likely to happen with this kind of attitude.