First of all, "replacement theology" is not heresy. It's traditional chrstian doctrine and always has been. Only the most Biblicist of Fundamentalist Protestants reject it.
Secondly, it's not simply the idea that the church has superseded Israel (G-d forbid!). It's the identification of chrstianity with a specific ethno-culture, ie, Europe, and the treating of Europe and Europeans as a sort of "chosen nation" of chrstendom. As the notorious Hilaire Belloc put it, "Europe is the faith and the faith is Europe!"
But it's not just Catholics who think that way.
Claiming “replacement” means no understanding of the new covenant, with all due respect. Consider that the first apostles mentioned were Jews for starters. FWIU, it’s an opening of the covenant to the other nations, not shutting out Judah or Israel; some may claim that Acts 18:6 is an affirmation of the doctrine, but it is not when Romans 1:16 is considered.
Interesting. Cultural conservative Romanists in Spain feel this strongly. One Spanish Foreign legion ( or as it is now styled ‘the Spanish Legion’ since non-Spanish citizens can no longer join) “Spain is , was and will be the Holy Faith and the Holy Faith is Spain now and until the end of time.” Very interesting fellow, his attitude towards Islam was sort of Uncle Adolph's above the Jews. He had served two tours in Astan.