I think it’s a Protestant thing.
When I was in the seminary in St. Louis, a number of us seminarians would go to the abortion clinic on Saturday mornings. On the one side, there were about 30 seminarians praying the rosary and singing hymns. On the other side, the parishioners from the Latin Mass community praying their own rosary.
Then there were these 2 or 3 Protestant guys. They would hold up signs of a mutilated fetus, and say things like “Don’t go in there, mom. Your baby has arms and legs and a heartbeat”. Sometimes they would say it’s wrong or a sin, so they were a little tamer than our OP spoke of.
Now, there was a woman from the Latin Mass parish who DID speak - but was mentioning (about 500 words a minute) other alternatives.
Here you have the contrast. The Catholics would pray and rely on God and the spiritual powers to defeat the Enemy. A rather silent witness focused more on trusting God to act. The Protestants would seem to rely more on themselves, on their own words and actions. They didn’t pray too often while they were at the clinic - they would just wait until the women got out of the vehicles and then gave their schpiel.
Oh, one interesting anecdote. One of the guys once said to one of the women, “There is one mediator between God and Man, the man Jesus Christ, who intercedes for us”. Apparently, he wasn’t really addressing the woman but was taking a shot at us for praying the rosary. After this, I saw one of the seminarians lean over and say something to him. I asked him what he said after, and he said, “I asked him if he would pray for me. He said 'Yes”. I said, ‘Thanks for mediating for me’". There was another seminarian there who would always approach him and whip out the apologetics on him, but he eventually left the seminary.