They do, it's not a theory, because they have stated it publicly several times. They say things like "he's in a new system again, and taking time to learn it," "we want to make sure he works on his timing and routes first," "We'd like if he adjusted to the short slants before we let him throw deep." That's how we come up with these "theories" because the coaches spew it. It's not like we sit around all day making excuses for the guy.
Seriously, take a look at our long history of worthless QBS, and show me one example of when we ever latched on to a guy and made excuses for him. We say what we do about Campbell's potential, because he has proven that it's there, he is just unable to gain the confidence of the coaches, because we have top dollar receivers who can't hold on to a ball when it's thrown to theit hands.
All Skins fans hated Tony Banks, Heath Shuler, Mark Brunell, Jeff George, Danny Weurffel, etc. We aren't delirious, we just wish that we could use the talent we had instead of keeping it on a leash because our coaches have no balls.