The techniques are all means of dealing with one simple idea: She wrote it. (That is, the "wrong" person--in this case, female--has created the "right" value--i.e., art.)
Denial of Agency: She didn't write it.
Pollution of Agency: She shouldn't have written it.
Double Standard of Content: Yes, but look what she wrote about.
False Categorizing: She is not really she [an artist] and it is not really it [serious, of the right genre, aesthetically sound, important, etc.] so how could "she" have written "it"?
Or simply: Neither "she" nor "it" exists (simple exclusion).