Tim,
I believe that Tom Sawyer's inclusion on a list called "Great Books
for Airheads" in the early 1990s suggests why Tom Sawyer is rarely taught in
high school or university classrooms. Academia dismisses Tom Sawyer
generally because he's not Huck. Bruce Michelson provides an insightful
discussion about Tom-haters vs. Huck-lovers in his book "Mark Twain on the
loose: A Comic Writer and the American Self." As a scholar fascinated with
the ways Twain uses Tom, I recommend a stop in that book before you finish
your article.
Any school banning Tom Sawyer for the reasons you detail fails to
consider the book carefully. The racism and sexism they insist exists in
the book needs to be tempered with an understanding of Twain's pervasive use
of irony throughout all his work. I suspect the fact that Tom is banned in
some places today has him snickering to himself in his grave.
Bill Hecker