Just for fun, I'm gonna point out that there's not really any such thing as an "Atheist Preacher" and anyone who claims to be one (or just acts like one) is most likely an angst-ridden teenager who "converted" to atheism because it's seen as "edgy." If they're too old for that, though, then they just never outgrew it.
Atheism doesn't come with a dogma. It is the LACK of a dogma. There's really nothing to preach.
That said, I don't really like some religious preachers... especially Evangelists. I condone religion because it gives other people something to live for, but really, those guys are just robbing people BLIND. Way to forget the entire basis of your religion, Evangelists. If J-dawg were alive today, his advice to them would most likely be this:
P.S. Apologies if that didn't embed right. I'm an embedding virgin.