Do you have anything beyond a few anecdotes to substantiate this? How much can you really know about the religious beliefs or practices of your therapists or psychiatrists? Unless they specifically identify with a religious counselling philosophy (eg pastoral counselling or something) most will keep their beliefs private as they would any other element of their personal lives. Their job is to help you figure out your issues, including your spiritual concerns if you have any, not share or impose their ideas about god or religion.

Also, in most countries (not sure about the US as it's often an outlier in this area) being highly educated tends to correlate with being less religious. So psychiatrists, who usually have 8-12 years of post-secondary education, would be less religious as a group than the general population on this basis alone.