No, that is a misunderstanding.
In a few weird cases you have British-born people who had non-dom status, but the vast majority are just foreigners.
Foreigners used to be able to choose to opt into higher UK taxes (eg give up their personal allowance) in exchange for having their foreign-sourced income that doesn't enter the UK be excluded from UK taxes.
In practice, it was high-income-high-wealth types who would choose that. So, foreign bankers, lawyers, etc. They paid taxes (at a high rate) on their UK income and gains, plus (after a certain number of years), an additional £30k or £60k pa on top. That was the ‘favourable’ terms they had before.
Now we will also tax them in the UK on the money that they earn overseas and which they never bring here.
That's in my view unfair, but from a sheer self-interested perspective it's probably a net drain on our tax take. So, we're paying money to get rid of some of our most productive (in economic terms) workers.
And the 'good riddance' sentiment feels misplaced to me too. These are people who only had any obligation to the UK at all because they chose to come here, and who have (almost certainly) been massively net-positive for the UK public finances.
The numbers aren't very high, but they pay for a lot of schools and hospitals.