It's a popularity contest. As much as we love our players, no one thinks that any of them are better or more impactful athletes than Randy Moss. I doubt any LSU fans would argue that Joe Burrow has accomplished more than Manning or Brady at this point. That wouldn't stop them from voting for Joe.
If someone wants to have a restricted poll, let them place it on a site where voting is restricted to members only. That happens all the time.
An open poll is like people voting for The Voice or AGT contestants. The best rarely win.