I think you are mostly correct especially if we consider the true biblethumbers. I just want to point out how to avoid original sin through baptism here, and it thus screws up your premise a little :) Aside that, I agree wholly on everything you said though. Although I must point out as well that Wicca is actually mostly based upon Eastern religions, among those Hindusim but it doesn't mean there aren't elements which can be found in Christianity as well. It also of course depends on which Wicca we are talking about, but what I personally think make Abrahamic theists to despise Wicca is that it puts women equal to or even above men; and that the female is an equally important part in the world foundation in comparison to an absolute male ruler. Even though most people don't really say or admit flat out that god is most often considered a man, we can more less assume that is the case, sadly.
The problem in this case is that religious people lack education about the very thing they propagate so much, namely theology. They de facto think that an atheist must necessarily hate god (in their world the lack of belief just doesn't exist, they cannot seem to generally grasp the concept itself) and since theistic satanists hate god, then atheists too must be satanists. Of course, they also mix up Laveyan satanism and theistic satanism as well; afaik, few of the latter actually exist at all.
I have to be honest, i think it is a sterotypical generalistaion that christians especially consider anybody who do not subscribe to thier belief system as being evil. Indeed there was proof of this during the early period of christianity where followers of Ba'al ze bub ( an emergent alternative) ended up being outcast, and there god had his name twisted from Ba'al Ze bub (lord on high) to beelzubub (lord of the flies). and as a result the god was deemed as the anti christ, almost as a way of evolving a survival strategy for ther religion by using rhetoric, lies and mis-information.
As to whether atheists do bad things because of unbelief is unfounded. Yes there are and have been bad athesits ( just look at Stalin) but on the whole we experience low crime rates, lower divorce, and happier home lives. You only have to look at scandinavia for that who have some of the lowest crime rates in the world, but the highest rate of atheists/agnostics