Why in the heck all of the sudden is this one particular politician required to be squeaky clean?
Because this particular politician represents the largest threat to career ruling class seen to date.
His election of an "amatuer" who was not a lawyer nor spent decades in various offices is completely outside the norms that have been established since the progressives won in 1913. Since that time, the average tenure in congress has gone from the 3.5 years it held steady at for the first 190 years of our existence to the current 10.5 years with 224 our of 435 members holding 37 or more years in office.
https://fas.org/sgp/crs/misc/R41545.pdf
The careerist simply cannot allow this model to continue. If the people think those successful in the private sector will make good electable leaders in Government then it will destroy their self licking ice cream political machine where only the careerist ruling class know what is best for us.