How do you "give respect" to people who, given half the chance, would literally ship you out of the country you've built your life in for the last two decades?
How do you find "common ground" with people who are seriously convinced that your mere existence is robbing them of something they cannot coherently articulate, when all the facts are that you are actually helping their own welfare?
I am afraid you have no idea what being an European (or most other ethnic minorities) is like in 2019 Britain. For us, this is not your standard dinner-party "lib vs con" parlour game, or the occasional shouting match at a family reunion - it's the difference between being a citizen in a modern democracy and being something very close to a Jew in Brüning's Germany.
When people are right-wing extremists, they can't help but bring up their BS in casual conversation. I've seen it many times. They live in an entirely different reality, where the basic facts simply are not the same as the facts you believe in, because they listen to entirely different sources of information. Talking with them is futile, as the OP said: who has time to try to dispel the crap disinformation, and it's probably not going to be successful anyway because why should they listen to you over the slick-sounding guy who has radio airtime? And what reasonable, intelligent person wants to be dragged into an unhappy political conversation every time he takes a cab ride?
You're right, all extremists are like that. The thing is, the OP was claiming that we need to talk to these people, respect them, engage with them, etc., even when we're just taking a ride in a taxi. My position is that, no, you don't need to try to talk to extremists when you just want to get from point A to point B, and also that trying to change these peoples' minds rarely works out.
Finally, no, singling out one group does not make you look like an opposing group's extremists. If you complain about neo-Nazis marching in your city this weekend, for instance, that does not somehow make you look like an extreme leftist. The simple fact is that right-wing extremism is very common these days among certain groups of people; you're probably not going to find any extreme leftists in a random rural American town, for instance.