William Weber, a LowEndTalk member, was raided by Austrian police in 2012 for operating a Tor exit node that was allegedly used to distribute child pornography. While he was not arrested, many of his computers and devices were confiscated. He was later found guilty of supporting the distribution of child pornography through his Tor exit node, though he claims it was unintentional and he was simply supporting free speech and anonymity. He was given a 5 year probation sentence but left Austria shortly after. Though some articles portray him negatively, it is debatable whether he intentionally supported child pornography distribution or simply operated in the legal grey area of Tor exit nodes.
Because they believe in what tor represents. It absolutely is used for terrible things, but it is also a pretty critical resource to a lot of people in a lot of dangerous parts of the world where thought crimes get people killed.
But yeah, no way am I running one. The potential costs are way too high.