The Catholics only started calling Baptists, along with other Protestants, ... brothers, ... about 40 years ago or so. For centuries before that ... we were called much worse.
And vice versa, what's your point?
That's not true.
The Protestant (and other) churches had no anathemas for Catholics.
Perhaps some individual Protestant believers, ... but none of the Protestant churches, themselves.
The founder of your whole religion (Luther) believed the Pope was the anti-Christ and that has been an official line of many revolutionary Protestant sects in the past and even some today.