The question of which written works should be excluded from the category of "literature" is a vexed one. Egalitarian critics would say that, since "Of Mr. Booker T. Washington and Others" is a piece of writing, it is necessarily a work of literature. More elitist readers, however, would demand some evidence of literary merit and intention. This, however, is quite clearly present in the writing of Du Bois, which is therefore literature according to any definition, however exacting.
The essay is, in fact, self-consciously literary in tone. Du Bois begins by quoting Byron, a respected poet, and continues with a poetic and precise description of the period in which Washington gained his ascendancy. He personifies the nation by describing it as being "a little ashamed of having bestowed so much sentiment on Negroes." There are many more literary devices employed throughout the text, rendering it both literary and rhetorically charged. They can be found in any paragraph at random. We can take the next paragraph (the second), for instance. It is short and dramatic in its commentary on Washington's ideas:
It startled the nation to hear a Negro advocating such a programme after many decades of bitter complaint; it startled and won the applause of the South, it interested and won the admiration of the North; and after a confused murmur of protest, it silenced if it did not convert the Negroes themselves.
The initial statement is followed by an ascending tricolon, made additionally striking by the anaphora and grammatical parallelism employed to encourage the reader to compare the reactions of the South, the North and the Negroes. It is, of course, for the reader to decide whether s/he agrees with Du Bois's argument or admires his prose style, but if this writing is not literature, it would be very difficult to provide either a definition or an example of what is literature.