This ruling does not stop at allowing discrimination against someone for their sexual orientation. It opens the door to discriminating on basically any feeling someone may say they have.
The four largest religions (Christianity, Islam, Hinduism, and a Buddhism) all address non-procreative sex and either discourage it or limit it to specific persons. E.g. https://academic.oup.com/book/522/chapter/135275904. It’s hard to think of anything that better qualifies as a sincerely held religious belief.