To be fair, I don’t think they mean it anymore. They’re just doing it out of tradition. Protestant inspired anti-catholic zeal is pretty much a dead issue everywhere in the UK except for certain parts of Glasgow and in Northern Ireland (Secular inspired anti-catholicism is another matter however)...
Secular imspired anti-catholicsm is strongly on the rise in the UK atm. Some of my Catholic friends tell me things have gotten really bad since the “Priest-Paedophile” scandal broke.