By the medical establishment and by the mainstream media.
Nobody wants to believe that convenient, efficient pharmaceuticals could be abortifacient. For one thing, that makes it a whole lot harder for Jane Catholic to say “contraception is a matter between me and my own conscience, Father X in my high school religion class told me so, and that’s the last time I ever gave it any thought”.
I don’t know about anybody else, but I had a “Father X”. He is now banned from the priesthood for life (though, for some reason, not laicized), for reasons that have nothing to do with contraception.