Answer
Misotheists are those who express misotheism, a dislike/hatred of God. The prefix mis- often refers to hatred or loathing. So, a misotheist despises God or religion in general, as a misanthropist (or misanthrope) hates mankind and a misogynist loathes women. The term misotheist is slightly out-of-date. The more common expression today would be antitheist, though misotheism technically implies a more emotional, personal level of disgust.
Part of what makes the term misotheism interesting is that it denotes an attitude more than any particular belief. It’s possible to be an atheist or agnostic and not be considered a misotheist. One can deny God’s existence without harboring an active loathing of God. Once someone gets to the point of feeling that theism is harmful and needs to be actively countered, he could be considered an antitheist. And those who are characterized by a particular hatred, condescension, or animosity toward religion would more properly be considered misotheists.
After the terror attacks of September 11, 2001, antitheism experienced a brief (and currently fading) swell of support. This “New Atheism,” as it is called, has been criticized, even by non-believers, for being intellectually and philosophically shallow. New Atheism is an example of a philosophy fueled by misotheism rather than by reason. Popular voices such as Christopher Hitchens, Sam Harris, Richard Dawkins, and Daniel Dennett have expressed more than mere disagreement with religion. Their approach is characterized by a visceral, emotional, and spiteful hate for all things religious. They are misotheists.
Today, misotheism is frequently seen in the work of comedians such as Bill Maher and Ricky Gervais and lesser-known scientists such as Lawrence Krauss. The public work of Neil DeGrasse Tyson, including the recent Cosmos television series, is misotheistic in that it presents religion in error-filled, unfair, and misleading ways. Not all unbelievers are antitheists or misotheists, of course. But misotheism is well-illustrated by the bigoted approach taken by these figures.
Scripturally, there is a difference between error and ignorance (Luke 23:24; John 9:41). But misotheists are not doubting God or relying on faulty reasoning to conclude that He does not exist. The misotheist is expressing willful, deliberate hatred toward God (Psalm 10:4; 14:1). He is the “scoffer” or “mocker” of Psalm 1:1 and 2 Peter 3:3. His spiteful rejection of God is warned against in the Bible in the strongest of terms (Proverbs 29:1; Romans 1:24–25).
Misotheism is an attitude immune to reason and to dialogue. “Mockers resent correction” (Proverbs 15:12). Jesus makes this point in Matthew 7:6, warning His followers not to bother arguing with those who despise the truth. Unfortunately, this means that the misotheist is best left to the consequences of his own choices. Those who actively hate God are not inclined to listen to the gospel or anything that disagrees with their prejudice.