Other western democracies go further than the U.S. with campaign restrictions, including restrictions to campaign financing. One might say they protect the functioning of their democracies more with these additional restrictions, protecting voters.
And one might ask why we don't want to protect ours more.
I'll swing wildly in the other direction with campaign financing and point out Bloomberg's run for president. He outspent everybody and won American Samoa. He wasn't unqualified, either. He was mayor of NYC.