An antitheist is someone who actively opposes
religion or even theism in general, which they make known in an egotistical, cynical, and overall self-righteous way. Ironically, a lot of them seem to enjoy berating and judging the same religious
people that they claim behave the same way towards them. Antitheists often think that they are intellectually superior to everyone else, yet they fail to realize that some of the greatest minds in
history were theists. These include Tycho Brahe, Galileo, Francis Bacon, Issac Newton, George Washington Carter, and Antony Flew (who was originally a staunch
atheist for over fifty years before converting to deism).
However, there is a difference between being someone who simply doesn't believe in God and being somebody who goes out of their way to bully and guilt
people for believing.
And before anyone assumes anything, I myself am agnostic.