Yes, as I said, the Nissayon is instant, and the problem is instant, too. The main thing is to have a filter that would block those images from appearing.
It doesn’t have to translate into thinking of yourself as a Rasha. I don’t see anything wrong with having the password, unless you know yourself and suspect that at a weak moment you will go on a clicking rampage. As long as your history is open and you’re not sneaky, just make sure the filter settings are properly set and go to where you are familiar.
In regards to Kefira, don’t underestimate it. There are attitudes about Yiddishkeit floating about, sometimes very subtly, that allow a coldness to everything seep in. Discussions are constantly brought up about Ikrey Emuna and all differing opinions are voiced. Someone with a weak backing in Torah, or someone who is more easily won over, will have those ideas creep into their mind. I can see on people who after being exposed to all these sites, seem like they just ate from the Eitz Hadas, and their eyes are suddenly open and they question much more than they did or should. But, I think I’ll agree that it isn’t as drastic.