The politically connected are not entirely shielded from legal problems. The Hillary haters are always going on and on about all the laws she's supposedly broken, and maybe she has, but so far I haven't seen her prosecuted for anything and I've seen plenty of politicians indicted.
Frankly, people who "trust" politicians are naive and don't really understand how politics works. Politicians who hold office are under various structural pressures and are frequently forced to make decisions that can easily be viewed as untrustworthy because they involve compromise, an art that is disparaged in our polarized political system. The bigger the politician, the more involvement they've had in the political system, the more they are viewed as untrustworthy. Sanders maintained his "purity" by his political irrelevance. This has become an asset now that the electorate wants change.