I was raised and baptized as a Southern Baptist, and am now blessed to be Catholic. In my experience, the Baptists I grew up with knew practically nothing about real Catholicism. When I grew up I knew no Catholics, had never seen the inside of a catholic church, and had vague impressions about Catholics based mostly on stories of the middle ages.
I was also taught that there had been Baptists since the earliest beginnings of the church, although not necessarily called by that name but at least persons who held exactly the same beliefs as Baptists. My teachers (who were wrong but knew no better), were therefore sympathetic to the reformation but did not think of themselves as being protestant.
While “hate” is too strong a word, I don’t think that Catholics were regarded as real Christians. This assumption was based on a complete misunderstanding of what Catholics actually believed and practiced. I had a vague impression that Catholics were a superstitious group of people who taught human traditions in place of the gospel, that they believed that crucifixes and holy water had magical power, that the thought that they earned salvation by following the orders of the pope & priest, and similar nonsense.
The actual beliefs of a well educated practicing Baptist and a well educated practicing Catholic are quite distinct, but they are closer together than ill-informed Baptists commonly assume.
Unfortunately, there are ignorant Baptists who assume that all Catholics are like the most outrageous of sinful and rebellious so-called Catholics. And there are Catholics who assume that all Baptists are like the most ignorant, prejudiced, and hateful Baptists who preach hatred for and lies about Catholicism.
Let us work to clean up our own house, and pray for our separated brethren.