This was one of the stupid things that was touted as a benefit of not being in the EU during brexit.

That we'd still have to comply with EU rules if we wanted to trade with them, but we wouldn't have any vote in those rules

Well, the Brexit campaign was manipulated by a state actor (or rather: 'a criminal actor disguised as a state'). None of the alt-right nationalism is in the long-term benefits of the country. This is globalism, the end game. You either team up, thereby reducing your costs, or you get swallowed. Ask Ukraine, Tibet, Hong Kong how it worked out for them not belonging to a bigger team. So divide and conquer is a logical move for the opponent, and it happens to align with alt-right. There is also documented evidence of external influence in these. A medium such as Follow The Money has documented such in various of their articles.