Wiki - The paradox of tolerance states that if a society is tolerant without limit, its ability to be tolerant is eventually ceased or destroyed by the intolerant. Karl Popper described it as the seemingly self-contradictory idea that in order to maintain a tolerant society, the society must retain the right to be intolerant of intolerance.
IMO the issue with this is that it's a binary: tolerant vs intolerant, and nothing in between. If you think of what it is if it's a spectrum, that's just called "having opinions", and letting your opinions decide how tolerant you are of others.
“I'm pretty tolerant person, but trans people should just die” is just an opinion. “Gay people should live in internment camps while they get cured of their disease”, is also an opinion. “Black people are just naturally inclined to live in slavery, it's easier for them that way” is also just and opinion. “It's perfectly OK for a 12 y.o. girl to marry a widowed man if her parents agreed, it's the natural order”, look at that, another opinion. “People with disability shouldn't be allowed to reproduce, it's unnatural and they risk spreading their disease”, one more opinion. Where do we draw the line? Where's the spectrum?
People easily forget that intolerance is also very selective and targeted. The vast majority of people with intolerant ideas would look pretty regular and normal most the time. The line is pretty clear though, someone's dignity (or straight up their lives) is stripped from them. That's not rocket science, it's not an unsolvable moral conundrum, or a spiritual mystery. If someone's dignity and life is being done away with, then you are looking at intolerance.