If a belief is so shallow it cannot stand up to criticism then that belief is not worthy of continuing to exist. The problem theists have isn't the criticism they rightly attract, it is their inability to logically or empirically substantiate their position.
If certain topics were off limits then this would become an echo chamber. However every topic on here seems to be open to criticism. This can only be good for how else would a reader be able to weigh up a subject if there were only people participating who agreed with each other. Now, what a reader will see is that some subjects are backed up with evidence and some subjects exist only because people know how to string a sentence together. The ability to critically analyse a topic is something that ex-JWs need to learn, having spent most of their lives being taught not to do just that by the entire organisation.
Visitors to this site don't have to post. In fact, the best thing to do at first is just read and get to know the personalities of the main posters. If anyone were to read the topics on this site about theism I am sure they would quickly see that the aggression and personal attacks come from theists in the main and that there is a common theme in these topics i.e. the position of theism is not rational or logical or backed up with anything more than a wish for something to be.
If people are put off by the tone of this site then I feel that they are not yet ready for the real world. However I would be surprised if any visitor to this site would be so thin skinned. Yes they may complain like a child that has been told they have to share their favourite toy but they would still come back and read. And who knows, maybe they will follow a link, do some reading and get a taste of what real learning feels like.