I never heard anything like this either, and in fact my own experience was opposite that of the author's: the precision emphasized in law school simply adds an additional dimension to the enjoyment of prose (or, once in a great while, poetry).

The whole idea that "thinking like a lawyer" should mean you forget how to enjoy reading and writing reminds me of Keats' claim that Newton destroyed the rainbow by explaining it. It's unfortunate that the author had such a bad experience with the law - but this is either strikingly bad pedagogy or simply a poor match with her specific personality, and shouldn't be taken as a reflection on the practice of law itself.