That depends who you ask. I don't think religion is unalterable, for example, but in the USA it holds a privileged legal position for historical reasons - although courts have concluded that merely claiming religious status is insufficient, eg https://www.ca10.uscourts.gov/opinions/18/18-1141.pdf

In general the Us recognizes race/ethnicity, sex, sexual orientation (to some degree) and religion as 'suspect classes' deserving of protection. But it's a thorny subject and understanding all the different perspectives is going to require a lot of reading.