The Paradox of Tolerance disappears if you look at tolerance not as a moral standard but as a social contract. If someone does not abide the terms of mutual tolerance, then they are not covered by the contract. By definition intolerant people do not follow the rules so they are no longer covered and should not be tolerated.
A good reply I found online:
The Paradox of Tolerance disappears if you look at tolerance not as a moral standard but as a social contract. If someone does not abide the terms of mutual tolerance, then they are not covered by the contract. By definition intolerant people do not follow the rules so they are no longer covered and should not be tolerated.