If you're not aware of what Roseanne said of atheists on Twitter I'd advise reading these excellent blogs before continuing with this one.
http://www.patheos.com/blogs/friendlyatheist/2015/12/31/roseanne-barr-calls-atheists-very-anti-semitic-on-twitter-and-then-keeps-going/
http://www.patheos.com/blogs/danthropology/2016/01/roseanne-barrs-atheist-bashing-and-our-chitchat-betrays-a-common-ignorance-of-atheism/
Okay, now my own encounter, which is in the form of an open letter to Roseanne.
