Why is POTUS bringing Pete Rose to people's attention now?

I'm struck between the severe punishment for Rose for gambling on his win compared to Bernie accepting payoffs to lose.

Supposedly Rose only gambled on his winning, but consider for a minute-

What would happen to an athlete that accepted payoffs to purposely lose a game? Imagine how furious the public would be.

Why do we even tolerate a politician accepting contributions and other bribes, with clear evidence later that the pol purposely lost their race?

The administration of our government is a much more serious matter than some guys who play catch for a living.