I feel that the premise of equality, which is one of the central arguments/basis of the liberal movement, owes itself to spirituality. Perhaps/maybe through Buddhism, when those guys preached equality against the Brahmanical order.
Much of the new age movement is also very inclusive.
The book “The Secret” talks about a gay guy’s experience with LOA- He wrote a letter to this LOA guru and talked about how he’s teased and ragged at his workplace for being gay. The guy responded by saying that you just focussed on all the bad shit happening in your life, so why don’t you focus on the good things happening in your life (gratitude) instead. After following this advice, all these negative people left his environment and he finally became the comedian he aspired to.
There was a black woman mentioned in “The Secret” book who learnt to love herself.
Deepak Chopra has also talked about gay spirituality and there are many blogs/gurus/healers talking about the same.
You can be black, white green, Asian, Caucasian but still be happy, successful and a winner. Your birth identity can’t stop you from becoming wealthy now. That’s the belief that most of the Spiritual industry holds.
This emphasis on equality and the power of thought as defining one’s role in society is also what drives liberalism. Hence, the two are connected.