Why weren’t there massive strikes and protests? Why wasn’t London completely shut down if such a large part of the people there felt like what was happening was not what they wanted.

There were dozens of enormous anti-Brexit protests in London and in cities across the country over the course of several years.

It wasn’t like this was a quick thing either, this went on for years, with the EU saying multiple times the UK didn’t have to leave and could just remain if they wanted.

Because the party that was in government had been taken over by fringe Brexit extremists and didn’t care what the British voters wanted. Even then, they struggled to get enough of their own MPs to support them which is why it took many dozens of chaotic votes over several years - plus an illegal suspension of Parliament that the courts had to step in to overrule - before they were able to ram their deal through.

Even at the 2019 general election, a clear majority of voters voted for parties that were committed to a second referendum to allow us to stop Brexit, but the Tories ignored the voters and went ahead anyway.

You seem really uninformed about the nature of the Brexit debate in the UK between 2016 and the UK’s exit in 2020.