Simply put, Catholics for Choice reject the teaching of Catholicism.
From Live Action News:
One of the most strongly held beliefs in the Catholic Church is that of the sanctity of life. This is why you cannot be Catholic and also be pro-choice… or, more accurately, pro-abortion. Yet there are those who think they can ignore the Church’s sanctity of life teaching and still be Catholics in good standing. Even worse, some of those people use their faith to try to convince other people to stray from Church teaching and promote abortion.Absolutely nauseating.
And that’s exactly what Catholics for Choice just did. They just took out a two-page ad in Politico urging Americans to stand with abortion behemoth Planned Parenthood.