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one of those who, one of the things that

In these constructions the verb following who or that should be plural to agree with the antecedents those or things:
            defacing books is one of the things that really bother me
            he is one of the 30,000 young people who pack a suitcase and head for London
            one of those archetypal Londoners who seem to have stepped out of Mary Poppins

The logic of the plural can best be seen by turning the sentence around:
            Of the things that really bother me, defacing books is one.