Those former Catholics who have been truly saved were saved not by joining a Protestant congregation, but by grace through the means of faith in Christ alone.
Those former Catholics likely came to understand Rome has another gospel. My church has a number of these folks. Most all of them still have family members in the Catholic church, as do I. We don’t hate the Roman Catholic people whatsoever, we hate the false religious system that has ensnared so many souls, some of them souls we dearly love.
It’s only natural for people to have negative view of a system that was leading them, and may still be leading love ones, into the abyss.
Your post is right on the money. Thank you for saying so.