We should be careful not to stereotype a whole faith based on the behavior of a few of its adherents. Each person is unique, although undoubtedly some SDA people are not very nice toward other faiths. The same can be said of Catholics, Methodists, Eastern Orthodox, etc.
I think SDA followers dislike what they think the Catholic Church teaches, which is probably not the same as what Catholicism actually teaches.
While the behavior described by the OP is definitely bad behavior By the SDA people, I also remember that Desmond Doss of “Hacksaw Ridge” fame was also SDA and rescued plenty of soldiers in WWIi, many of whom were undoubtedly Catholic.
He was a “salt of the earth” kind of guy and a very good man, based on his actions. And he was a devout SDA.