Shouldn't someone who constantly lies, slanders evolution,and defrauds people be prosecuted and sent to prison?

Hovind was sent to prison because of tax-related crimes. You slander *people,* not ideas. The error that Hovind was making was the same one that all creationists without exception make: the straw man fallacy. While slander *is* a crime, committing the straw man fallacy is not.