I and several other authors have joined numerous groups on facebook in an effort to not always be promoting to other authors. It really is a shame when spam occurs because someone decides to promote ‘handbags’ on the Babylon 5 group page.
When a person posts the review of an author’s work without a link to purchase in a literary group how is that spam? It isn’t.
How many believe that groups pushing for development of a segment of science should embrace literature that promotes their science? All of your hands should be raised.
The point of this is that social media is here. You may not agree with what goes sailing around on it but that doesn’t entitle you to attack the sender. It does give you an opportunity to express a view and to behave like an adult.
If the rules of the group haven’t been violated then you have no business lashing out.