Assimilating doesn't mean changing one's personality. I'm still the same person I was before I came to the USA, but I respect that some things are customary and others are considered offensive. I know I'm expected to tip for services that in other countries would be considered insulting. Yet if enough immigrants refused to tip, it would become a stereotype that would create negative sentiment towards said immigrants because workers rely on that income.
> If you think a fraction of a percentage of people coming to the UK is suddenly going to change the identity of the entire country then you need to get out and explore more of the UK yourself.
I roadtripped across the UK earlier this year actually, spending time in 2 major cities and 4 small towns. The demographic shift over the last decade is immediately noticeable. It is multiple orders of magnitude more than you're making it out to be.
> I do think it’s courteous for people to make an effort to integrate. But it should also be their decision, not ours.
That's a matter of opinion, and perhaps not up to either you or me to decide whether it is right, but up to the % of citizens who will vote against immigration at the next election. Unchecked immigration is the top reason that western populations are shifting rightward. And this trend has evidently scared the Labour Party enough that they're finally preteneding to do something about it.
But let's say it is up to an immigrant to decide whether to integrate. What if their values are incompatible with the country's? If you move to the UK and take great offense over how people dress or their type of humor or their freedom of religion or their pub culture or whatever, why did you even move there? And if you then expect this entire sovereign nation (who is already doing you a favor by allowing you in) to change their ways to accommodate your beliefs, that is a hell of a lot more entitled than the other way around (the country expecting an individual to integrate as part of the terms of being let in).