You need to stop repeating things that are not true. His charges had nothing to do with the election. They were "falsifying business records". This law has nothing to do with elections and it is not a arguable point. Also, "manipulate the election" is a completely meaningless phrase.
Nope, you can't argue out of both sides of your mouth on the electoral bit.
Yes people are rarely prosecuted for this crime, because its usually not worth finding out and dealing with. His was found because in this particular instance his crimes were found because he was committing them while trying to manipulate the election via hush money payments that were connected.
You're either one of the sanewashers for this guy or the ones who fell for his shtick, but just because he's constantly committing crime all the time, including while engaging in politics, doesn't mean he has an aura of protection because of it