As pp said, there is a lot of money and organisation behind these demos.
duck://player/tZYNk9OSF_E
https://www.msn.com/en-us/news/other/european-parliament-votes-to-confront-muslim-brotherhood-islamist-entryism-in-overwhelming-vote/ar-AA2etD58
The dream of 50% of children having the opportunity for further education straight from school means that even more young idealists get exposed to ideas they don't have the perspective to interrogate, it was a known 'cold war' issue for oxbridge. They move through into teaching, the unions & civil service. They are often a cheaper hire with energy & enthusiasm but limited experience.
In the UK we influence & are influenced by other cultures that settle here. We should aim to assimilate the good and reject the bad. At this moment in our history we have that arse about face. Sectarianism is destructive, and this movement is sectarianism in action, you'd think with our past we'd recognise it when we saw it.