Elton John is mega-rich and is not a US Citizen, as well as surely having very well paid lawyers, so does not have the concerns that others have. Furthermore, many churches are accepting of LGBTQ folks and will perform marriages, including one in SF where a friend of mine used to be a pastor.

Rights are not about not upsetting people. If noone did anything that upset people, it would also be illegal to marry interracially. A lot of people alive today have a problem with that, and the government said: too fucking bad, kiddo.