It seems like Paul is confusing intolerance of intolerance with heresy in this essay. Further reading: https://en.wikipedia.org/wiki/Paradox_of_tolerance Expression of just about anything is met with fairly minimal consequence at least in much of the US, but nonetheless, there's a difference between not accepting something versus being intolerant of it. E.g not accepting [way of living] in one's own daily life v. not…
To quote Popper (this is also quoted in the wiki link you posted):
> In this formulation, I do not imply, for instance, that we should always suppress the utterance of intolerant philosophies; as long as we can counter them by rational argument and keep them in check by public opinion, suppression would certainly be most unwise. But we should claim the right to suppress them if necessary even by force; for it may easily turn out that they are not prepared to meet us on the level of rational argument, but begin by denouncing all argument; they may forbid their followers to listen to rational argument, because it is deceptive, and teach them to answer arguments by the use of their fists or pistols. We should therefore claim, in the name of tolerance, the right not to tolerate the intolerant.
Which is fair. If someone is going to respond to you by beating and shooting you, you shouldn't have to tolerate them. The justification for the intolerance of the intolerant is that the intolerant use violence to get their way.
But rounding up a mob because someone holds an opinion is not what Popper is describing. It is much closer to hunting down heretics.