one can hardly ever be something like too humanitarian, or too humanistic. — but one can be too anthropocentric (as vegans do good work in informing us about). — or, indeed, one can be ‘all-too-human’.
that is: we submit this concept as referring to the erroneous & unethical aspect of human-to-world relations, and human interpersonal relations. i.e. it refers to unethical behavior such as snobbery, classism, racism, sexism, and other types of biases & prejudice which are very old and outdated human society problems, and which have plagued humanity in a very special way compared to other species—thus: all-too-human.
(this is a readaptation of Nietszsche’s concept, for the purposes of 21st century [post]humanism.)