I find this rather difficult to swallow.
First, can a church "without dogmas" properly be called a "church"? What would distinguish such an institution from other charitable and social-uplift organizations such as Oxfam, UNICEF, CARE, the Salvation Army, and so on? If all it does is "good works," then it is no different from secular organizations that do "good works." And if it is no different from secular organizations, then why call it a church? The very essence of "church-hood" is the adherence to a unique set of beliefs about God, man, and the world. What holds the church community together is the common set of beliefs shared by its members, beliefs that are held as a condition of membership. One cannot get baptized into a church without affirming the dogmas of that church. A church without dogmas is as unthinkable as a brothel without prostitutes. I wonder what Dennett would say to a brothel whose inmates did not engage in sex in exchange for money, but went around feeding the poor instead, or provided in-home care for bed-ridden old men. I wonder if he would still call it a brothel.
Second, the moment atheists (or agnostics, or secularists) form a church-like community, atheism (or agnosticism, or secularism) will devolve into a religion. This is precisely what atheism (or secularism) is against. Atheists are atheists because their atheism gives them the freedom to think what they like; it does not bind them to any particular set of beliefs. A "church" of atheists would immediately turn atheism into a system of beliefs and would require adherence to those beliefs as a condition of membership. This is the very antithesis of atheism.
Third, I find it rather mercenary to want to be a memeber of a church or similar "community" merely for the sake of having someone to love you and take care of you when all else fails. Christians are required to love one another by the tenets of their faith (and, of course, by the express injunction of Christ to do so). But Christians are not members of a church simply in order to have someone to love and take care of them in time of need—or at least they should not be. That would be a prostitution of Christianity. Christians are (or should be) members of whatever church they attend because they are followers of Christ, regardless of whether they will have someone to fall back on when they are destitute. The love and caring of the Christian community (such as it is) is merely a side benefit—the icing on the cake, if you will.
Loving and caring can and does occur across religious and sectarian lines. In countless communities around the world, Muslims show caring for their Christian and Jewish neighbours, and Hindus help Sikhs, and Catholics and Protestants come to the aid of each other in time of need, and non-believers take care of their religiously inclined fellow community members when it is called for. Churches don't have a monoploy on loving and caring.
The last thing the world needs now is yet another church. And the last thing that non-believers need is to mimic the behaviour of their believing counterparts. Anyone who does not have the courage (or strength) to be an atheist entirely on his or her own, even in the face of opposition from the entire rest of the human race, is not worthy of being an atheist. If you want community support, go become a Christian! After all, there already are, according to Dennett, "churches without dogmas," so a non-believer or secularist, according to him, should fit right in at some such institution. Where, then, is the need for secularist churches?
Atheist churches? Come now, Mr. Dennett!