A church filters on religion (somewhat, many welcome respectful outsiders). A company or software project filtering on religion is very different.

They are, of course, free to do so; freedom of association is their right. Others are free to judge them for it, and to question whether they should be using the resulting software. The license is open, the community is not. So, seeing a project come along that looks to build something more open (and it's really saying something when "project whose governance is owned by a company, but open to pull requests" is more open) seems like a positive step.

(Also, as a database project, surely they shouldn't be mixing church and state. ;) )