That has an awful lot to do with what "the thing" is. I'm sure there are a few people out there doing it just to feel more important, but often there's a good reason for denying someone access - either it's just a terrible idea to begin with or they don't know you well enough to trust you without someone else (i.e. their boss) specifically requesting it.

I could be off base here about your experience, but I know that some people made the same comments about me when I pushed back on sharing dangerous credentials with inexperienced coworkers. Damned if you do, damned if you don't.