Huh, that's funny.
See, I Googled "the single most impoirtant rule in MLB and it didn't come up with anything about gambling.
The Hall of Fame pays tribute to those who performed better than their peers. Nothing Rose got in trouble for enhanced his on-field performance. There are a hundred ways he could be sanctioned while still allowing him into the HOF.
Bonds, on the other hand, was taking illegal substances to enhance his performance. It wasn't Bonds, it was Bonds and drugs and, for that reason, Bonds should be banned from baseball for life...