For some people it is. However most married men do not need the services of prostitutes and porn stars. Those in politics usually do the smart thing by asking for forgiveness and working it out. Then going before it becomes a media
You need to understand what the FEC considers and election contribution. According to the FEC, A contribution is anything of value given, loaned or advanced to influence a federal election. It does not have to be given to the candidate's campaign fund. If you put a billboard up in your front yard that says Elect Trump, that is an election contribution. If you pay rent on a town hall for a rally, that is an election contribution. Cohen paying hushmoney to Trump whores, etc is an election contribution because Choen did it to influence the election.
Cohen was the sacrificial goat. He pled guilty to illegal election contributions, exceeding the individual limit, and falsifying bank documents used in the hushmoney payments, all as part of a scheme to protect Trump. I don't think anyone believes that the hushmoney that Cohen paid was done without Trump explicit instructions. However, expecting Trump to be charged in 2017 would have been nuts. with Trump appointments to the DOJ, FBI, FEC, etc and a republican congress rubberstamping them.