There's an interesting article in the UU World this month, about beliefs that UU's don't tend to have. You can find it here. But the editor was apparently confused by the first paragraph and added a pull quote in big letters that is a dreadful misunderstanding of the concept of "Welcome." ("Signs by doors say, 'Everyone welcome here,' but we know it's not true. If you hold some beliefs, you may not like it here.')
But whether a person feels welcomed to a congregation and whether they like it there are two very different things. Although a poor welcome lessens the chance that a person will like the congregation, it is not only possible but likely that some people who feel fully and warmly welcomed will also, after a time, decide that this is not the right community within which to nurture their spiritual life.
That was actually the point that the author was trying to make, and she went on to list 10 beliefs that a new person might have which are dissonant with some understandings of UU Principles or with commonly held beliefs in UU congregations. (Although I must say that I have known individual UU's who have held one or another of the 10 beliefs discussed and didn't leave. Some went so far as to insist that they not only were not in the minority, they were "real" UU's. But that's another story.)
The confusion in the pull quote mirrors a confusion I have heard often enough, which is a confusion between "Welcomed" and "Happy".
The two are very different. To welcome someone is to say, "We are glad you are here." Welcome requires the basics of hospitality; that we let strangers in, share what we have, treat them with dignity. This is hard enough and we don't do it very well and should work on doing it better. However, hospitality does not require that we bend, pinch, and change ourselves so that everybody who comes to us will like us and feel well served by what we have to offer.
The difference between a creedal and non-creedal church is that when there is no creed, it is up to each individual person to decide for themselves whether they belong here and are well-served by our way of doing religion. No outside force will say, "Because you believe this, you are not welcome." (Sometimes the congregation has to draw lines about behavior; that, too, is another story.) Instead, each person looks around and says to themselves, "I think I could grow in spirit here.", and stays, or "This is not for me," and goes. This may (or may not) signify a failure of mission for the congregation, but it does not necessarily mean that their welcome was deficient.
The Signs by the door should say, "Everybody Welcome Here!" but that doesn't mean everybody will decide that this is the right place for them. And that's OK.