Well, to help the TOR project it is not a requirement that you operate an exit node. You can donate your services/bandwidth as an entry node or a relay.
Whilst the existence of a service like TOR that provides anonymity does attract those that want anonymity for nefarious reasons, I think that it is fair to say that repressive regimes really hate
the TOR network as it punches holes in their state propaganda machine, and allows communication between the inside and outside of their network of control.
Conspiracy theorists may consider that obnoxious content transmitted through TOR may, in some part, originate from the regimes that wish to see web anonymity's demise. (?)
The Google corporation seem to hate TOR too: They certainly seem to prevent use of their search engine from exit nodes. I think it is because it spoils their data model for collection of information about individual users' behavior online.
Search engines like StartPage
are friendly to TOR usage.
I personally think the the freedom to say what you think without having to publish who you are, is actually a cornerstone of democracy i.e. the secret ballot.
Certainly, before you set up a TOR exit node, you should understand the risks involved, but it's not the only way to contribute to TOR.