I think the "-porn" suffix is part of the internet vernacular now. We'll probably be calling porn pornporn at some point. We're stuck with it just like we're stuck with "-gate"
I agree with the other posters that this is just internet nomenclature in general, but I have noticed that some people are referring to Lemmy “communities” as “sublemmies“. Fortunately, I don’t think the name “kbin” really lends well to such an analogue so we can just continue to call them “magazines”.