He can't talk to the right people, he doesn't have enough evidence, and he wouldn't want mass panic. And the one who has all the proof he would need is the one person who would turn out to be the most mistrustful.

Yeah, that Senatorial race, which first frustrated me as another method the writers chose to show how evil Lex could get, when in fact it shows that Lex would do things even at the risk of losing what's left of the Kents' good will towards him in order to get into the position of power, and I wouldn't fault him for wanting that, considering what he knows of the dangers he wants to protect the world from (i.e., rogue mutants and aliens).

Clark is naive in a way that he doesn't know what he and his actions look like or what he represents to other people. And... I think his feelings for Lex are complicated. :D