That just makes me think, when he says "Heard", he actually means to say "Listen" as in he hasn't listened to their music, and therefore hasn't heard of them.
And it's also possible to be aware of someone and not know every project they are involved in. You can know a person based off an unknown project or some other way, without knowing anything about their major project.
It's easy. They don't go onto forums, or Facebook, or anything online, and go out of there way to look for these bands or interests that many of us lovers of prog music do. They just make music, and do interviews, and live their life outside of that music world. Some musicians neglect that entirely while enjoying their life.