Why are Tolkien fans usually left-wing?

[The Might]

Before I explain more about why I'm starting this thread, I want to make it very clear that it's not about discussing politics and who is right or who is better.
I respect all political positions as long as they do not belong to any of the extremes and I hope the same will be done within the thread.

Anyway, this Saturday I attended a meeting of the local section of the German Tolkien Society. It was great fun to meet more Tolkien fans in real life, we played the good old "Who am I?" game (I was the Gaffer) and discussed all kinds of M-e related topics.
However, the topic of the recent elections in our state was also brought up and everyone agreed that the change in leadership (from the Christian Democratic Union to the Green Party) was a good one.
Furthermore, ever since I started posting online on Tolkien forums, even before I was a BD member, I couldn't help but notice that the large majority of fans were left-wing supporters.

So my question is - why do you think that Tolkien appeals rather to people on the left? Is it the environmental aspect of M-e or the perfectly functioning system of the Shire that contribute? Is my assumption even true?

I'm looking forward to your answers and I want to again underline that this is not about politics, nor about which side you should support.