Adolf Loos, 1905, source: wikipedia
Can we separate the artist from his art? By implication we assume that outstanding personalities are supposed to have a high moral integrity. If the artist is outstanding we might take the personallity for granted.
Surely not for Adolf Loos (1870 - 1933). In 1928, architect Loos was accused of sexual child abuse. The court acquitted Loos in the absence of credible evidence to prove his guilt. However, Adolf Loos was convicted of seducing a minor and was sentenced to four month in prison. (for german speaking readers see "Pyjama und Verbrechen", by Andreas Weigel, or the german article in wikipedia).
I will always think that Adolf Loos has been a great architect, but maybe I will never be able to see his buildings without thinking about his misdoings.