Because the world is awash with porn, Ian, accessible to anyone within a few clicks. This is creating a lot of porn addled individuals who are so desensitised to what used to be ordinary standards of decent behaviour that they would regard looking at these sites and forwarding such images as a perfectly normalised thing to do.
In fact not only is it normalised, in the case of upskirting or revenge porn etc it's often considered a bit of a laugh. (I expect this will be LF's line of defence if he chooses to fight the charge, though he'll probably plead guilty).