Howdy ho...
My interest in sciforums is purely in the scientific topics, so unrelated threads like religion and pseudocience I have no interest in whatsoever. Is it possible to filter these out so they don't appear in the listings? I've had a look around, and can't seem to find a method, though I'd have assumed it would be a logical option to include in messaging software such as this.

Well, you can subscribe to forums of interest. These then appear in your Control Panel under, obviously enough, "Subscribed Forums". This is the only way to get a subset view of the forums.