Yet tolerance itself is a disvalue as post modernists would have promoted it." what are some of the things that those who advocate tolerance cannot be tolerant of

This text means that you can be tolerant to some things or situations but there are also some situations wherein tolerance shouldn't be practiced, like when you see people doing bad things to others. The things that people should not be tolerant of are people such as racists, killers, rap! sts, and other kinds of people who do bad things.