(NSFW) Isn't this simply...rape?

I was looking at some porn (for educational purposes, of course) and I came across a whole category called simply “sleeping.”

The women, and more often than not girls, were sleeping, either from drunkeness or drugs – as they would not awaken when, ahem, well, I guess the proper term should be “raped.” I mean, they were sleeping – so it wasn’t exactly consensual, right?

The girls are always filmed where their faces can be seen. Many are under-age – but whether they are or are not – isn’t it simply rape anyway?

Some of the men’s faces can be seen – no-one seems to be afraid of prosecution.

I do not understand how this is possible, let alone legal.

Could someone explain this horrific phenomenon to me?