I think you might be using the term street cred as a literal definition. When I say street cred, I mean a guy that can walk into a club and not usually get the stink eye or a kid you grew up with that nobody wanted to fuck with because he looked tough. Yes, these types can be exposed an lose that cred, but what I'm talking about is how they were gifted it to begin with, where a smaller guy has to earn it.
Anyways, it's human nature. Obviously not everyone is going to overestimate a guy that's significantly taller than average, but most people do. Just look at Sherdog, posters do it constantly with professional fighters, and that's guys that are into fighting that should know better. A guy that's 6'2" is going to be far less likely to get "tested" literally anywhere than a guy that's 5'7" with a similar build. To say otherwise is to deny reality.
Honestly, I think we're talking about the same thing, where a guy that was tall could get exposed as a kid. They know they'e not tough, and we know they're not tough, but people that don't know them have no idea most of the time. They get instant street cred that smaller guys don't receive just for being big