Well, as you may have guessed, I've kind of already tried that. The thing about liberal religion in general is that it's a crapshoot at the group level. I attended a Unitarian church in Austin a few years ago that was actually pretty cool, and probably the only reason I didn't come back is I was really trying to do something else at the time (more on that in another post). But I don't live in Austin any more, and my Unitarian experience where I currently live has left me cold for a couple of reasons.
You can probably guess that I have little patience for fundamentalism of any stripe. But there are other things that I hold in almost equal contempt. The first one is New Age bullshit. I thought about finding a more polite phrasing, but I think it's necessary here. If you value science at all, the belief that you can't sign a contract because Mercury is in retrograde is no more tenable than some Middle Eastern guy who lived a few thousand years ago managed to get every species on the planet onto a vessel about one-third the size of a modern aircraft carrier. Obviously, not every liberal believer has these views, but often such views are spared the skepticism they deserve in the name of tolerance and respect.
The second issue I often run into with liberal congregations is actually the flip side of the same issue I've run into with conservative congregations: I don't like politics being preached to me. At first it was a little easier to stomach when it referred to politics I generally agree with, but I've come to find even that distasteful. That whole "separation of church and state" thing? I'm a huge fan of it--in both directions. So this, combined with the previous paragraph, does not exactly make me a lot of friends in any kind of religion.
And that leads to the things I like best about "organized freethought," to the extent that there is such a thing: freethought groups are always at the forefront of promoting church-state separation issues and the teaching of proper science. You have the right to believe all the craziness there is on this planet if you want to, but the second you try and tell me I need to believe something, well, you'd better have some evidence for it, especially if you want to write these beliefs into law.
I highly recommend this post at Pharyngula that reminds us:
This is atheism: we have no dogma, we have no infallible leaders, everyone is naturally flawed, and we recognize that within our ranks there is a huge diversity of opinion. [. . .] There is no Atheist Supreme Leader. There is no Atheist Pope. There is no Godless Ruling Council, no Atheist Inquisition, no Freethought Dogma.
You could be forgiven for thinking otherwise at times. Remember that anytime you feel tempted to appoint yourself the Ideology Police.