isn’t a “Mass” specific to Catholicism?.....I always thought so...
I’m pretty sure these are Baptists
Not quite - it's not a term used by Baptists or most Protestant denominations, but nor is it totally limited to Catholics. Some Orthodox groups use the term, so do Anglicans (although they tend to use other terms more often, Mass is still considered correct), and I believe some branches of Lutherans do as well. There are other smaller groups that have retained the term as well.