B maybe did a crime, did not get caught. Never paid a debt. Maybe never learned a lesson A did.
This is not just politicians. People have feelings about this too.
Frankly, I believe in being able to pay ones debt, mistakes having been made, growth, better experience acquired, and move on.
If it is minor, there should not be life long implications.
Many crimes are not solved, and the crimes people are convicted of are a tip of the iceberg. Prosecutors commonly reduce the charge to get a guilty plea in a plea bargain. If person A has a criminal record, it's quite possible he has committed more crimes than what he has been convicted of.
No, commonly, they pile on every charge they can think of and come up with some ridiculous sentence for a small crime, then offer to reduce it to something reasonable in exchange for a guilty plea.