Really? Where do you see anti-catholic bigotry on Guy Fawkes night, the religious aspect of it is long forgotten and people dont really understand or care why it is a celebration, its just a bit of fun in the winter nights.
In Lewes for example (one of the biggest celebrations in the UK) they still burn an effigy of the pope every year. These days they burn Trump too, but the anti-Catholic traditions continue.
A particular quirk of British people is that we're very bad at stopping things that are considered traditions. We carry on with them long past the time they were relevant, maybe because none of us wants to be the one to question them. I doubt there's any anti-Catholic feeling in Lewes at all, but a lot of people who go along with burning an effigy of the pope because that's what they've always done.
When I was in the scouts (80s Britain), our local Catholic group organised a bonfire for November 5th, same as everybody else. We all knew about the origins of the tradition and the gunpowder plot, but I never caught any anti-catholic prejudice at all; unlike a few exceptions (Lewes, Northern Ireland), there didn't seem to be much heavy historical consciousness about protestantism and catholicism.
And if anything, I'd say that's even more true today; guys on bonfires are rarer, some events go off without a bonfire at all (just having the fireworks as entertainment), and so on.
I have been to bonfire night in many places in the UK and never saw anything other than the guy being burned. Lewes is not representative of the UK as a whole.