there were fears by the Protestant majority, that Catholics would take over and establish a Catholic theocracy. Sheer numbers and birth rates militated for this point of view. (Obviously the latter is not an issue anymore, not hardly.) Some people began to dig a bit deeper into the matter, came to the conclusion that when Catholics exist in sufficient numbers, and accumulate enough power, they will indeed take over the country, and remake it in accord with Catholic principles, giving the Church ultimate power…
So Catholics in public life had to distance themselves from this. If they ever hoped to have power in American society, they had to jump through hoops to assure Protestants that, no, we’re not going to force everyone to observe Catholic moral teachings, we’re not going to take over.
It takes the rural folks, the conservatives, the less urbane, possibly even less educated, the fundamentalist Christians in the “red states”, to see murder of the unborn for what it is, and really not to care if anyone thinks they’re “forcing their religion onto people who don’t share it”.