I agree with much of what you say. Far right views and attitudes are being normalised, and the degree of anger behind the views often expressed is scary too.
But I agree to a point with some of the posters saying "what about the left?" as well.
To me, the country is becoming increasingly polarised. Both the major parties and society as a whole. Its not that there aren't centrists anymore, but the centrists in parliament have very little power and centrist voters have no-one to vote for!
I am quite a lefty on many issues (not all) but I have more in common politically with a moderate Tory and centre right politics than I do with many of those who hold power and influence in the labour party.
The Conservative government is in thrall to the right wing fringes of the party, and there isn't an effective opposition.
The extreme left and the extreme right are feeding off each other, each one growing worse in response to the other. There's so much rage, and what seems like genuine hatred towards those with different political views.
I do think that Brexit has had a centrifugal force on politics, although its not the sole cause.
I expect that any economic downturn, or decline in living standard will make the divisions worse, it usually does. The less there is to go round the more people tend to turn on each other (especially if whipped up by those offering scapegoats in exchange for power).
As you know op there are figures with lots of money and influence behind them who want to exploit the situation to their own ends. It is not always easy to categorise men like Bannon as they don't fit into a neat political box, but many of his views do fit with far right ideology. Whatever you want to call these people, they are fucking terrifying and we should all be wary of playing into their game.