First off, I'll just say that I do understand the difference between Unitarians and Unitarian Universalists, but from the language used ("free to believe anything that they want", "liberals", etc), I think he's talking about UUs. Anyway.
Though I've been an Atheist/Secular Humanist/Non-theist for as long as I can remember, I grew up going to a Unitarian Universalist church until I was about 14-15. Those people were some of the most intelligent, most insightful and educated, most rational and levelheaded, most generous, kindhearted people I've ever had the pleasure to meet. I honestly don't think I've ever met a UU who was in any way bigoted towards any race or faith. No other affiliation of people that I've ever encountered has been their match.
Most of them (at least at the church I attended) were atheistic or at least agnostic, but many were "spiritual" (usually meaning they did stuff like yoga or meditation, not so much any of the New Age bullshit that's so popular these days). To the vast majority of UUs that I've met, UUism is more of a social outlet rather than an actual religion.
Youth activities tend to be either educational or fun or both, with the closest thing to religion being programs that teach about other faiths. Adult services are, for the most part secular, with topics like hope or emotional healing or joy or family or something (I don't think I remember ever hearing a single quote from the Bible). Maybe something pseudo-spiritual at Christmas.
I would really recommend everyone going to their local UU church for a couple weeks, get a feel for it. Even Atheists--trust me, you won't be alone. Especially check out what activities and such they have going on outside of the church itself. Poker nights, camping, public service, auctions, the list goes on and on. In fact, when I was growing up, there was a group of UU astronomers who worked at the U.S. Naval Observatory. Once a month or so, they'd get together a group of people to spend a night there. Good times.
Anywho, we had more than a couple Christian nuts "sneak in". They were more than welcome to join us for services and activities, but they invariably became... aggressive. I remember one man who seemed nice and sane enough all through the service, but afterwards, he was caught scaring the shit out of a little boy with his evangelical shit. When confronted by the mother, he turned violent and shoved her back onto her ass and was screaming that she was a liar and a sinner and she's going to hell, etc, etc, etc. My youth group leader called the cops on the guy. That's the most extreme case I can remember, but there were many whom we had to ask to leave.
UUs don't mind talking about God or religion in general, but when you start preaching and ranting and threatening in an irrational and intolerant manner, we won't stand for it. If your faith can't stand up to civilized discussion, perhaps you should re-evaluate your faith.
EDIT: Actually, that's not fair. I do now remember a Christian family that joined the church and became valued members of the congregation. There were probably a couple others who just never mentioned it, too, I guess.
