Since aircraft on parallel courses with lateral separation cannot collide, and since the trailing aircraft has the lead in his field of view and in a fixed positon in the canopy, it's clear the simplistic statement quoted is false
Being pedantic doesn't make the statement false in the context of this conversation, when I spent all my time flying trail with the other chap twenty feet in front we weren't on a collision course either.
If you see another aircraft maintaining a constant bearing you better keep an eye on it as you have no idea what track it is maintaining relative to yours.