Popper is clear. He’s not willing to extend tolerance to completely intolerant people.

Suppressing intolerant individuals makes one intolerant. The concept is symmetric whenever cancelation occurs.

That is very kantian. If someone came to your door and asked you to point to where your children were so he could murder them, would you tell the truth just because lying is wrong?

Similarly, would you tolerate hate speech that could put your life in jeopardy just because you believe in free speech?

The point I believe is not taking the ideal to its maximum blindly, but clearly defining boundaries you can't cross, even if it meant behaving intolerantly.

That part is clear. What is not clear is how does he determine who is intolerant enough to fall in that category. And also, what that proposal of righteous intolerance means. Does he stop listening to them? Does he de-platform them? Does he incite the mob against them?

No, you’re just being facetious. The problem is that for yall, everything needs to be sacrificed at the altar of free speech, even reading comprehension. This is exactly what Popper is saying: we can’t tolerate the intolerant because they don’t play by the same rules.