I think you've done a pretty good job of answering your own question. The change in question was first adopted by the Presbyterian Church in the USA in 1903, and was adopted by both the OPC and the PCA at their founding.
Fair enough. Thanks.
I’ve done a bit of looking, and I’ll expand on my comment slightly. Please understand, I’m not trying to bait you with these comments, but to answer a question you asked about something that happened over a hundred years ago.
The reference that I read indicated that there were two factors in the removal of the provision. First, as already mentioned were changes in the Papacy, and indeed the Catholic church’s position in society. Second, there was a recognition that there were others who would put themselves above Christ.