It's unfortunate, but the web is open to everyone with no discretion criteria. I believe those who display and distribute pornography in any form are trying to get your attention. It's been said a great defense is a good offense. Don't pay any attention to them. If they don't have an audience to play to there's no reason for them to exist.
I've gotten some interesting search results and I use the Limewire filters to keep out unwanted material. If something gets through to your system, don't even open it. Delete it immediately then filter it out.
We may not be able to stop the sickness but we don't have to give it any attention either.
All the best
itsbrkn