I think of the internet as a big city. As with any big cities, there are safe areas and unsafe areas. There are shopping districts and red-light districts.
No one has built a wall to keep me out of the unsafe areas or out of the red-light districts, yet somehow I manage to avoid them almost all of the time. If I happen to find myself in one, by accident, I leave quickly.
Also, is there any virtue for doing the right thing, if doing the right thing is enforced? We keep kosher not because it’s easy to do, not because it is externally enforced with filters and fences, but because we seek to do what is right, and eat in a holy manner. If all non-kosher food were to taste bad, would following the holy diet have any meaning?
Shouldn’t we be allowed to CHOOSE to do the right thing, in the face of temptation?