There will always be filthy sickos out there. If you are really concerned about what someone does on the internet at your public library, maybe you should work to get rid of the internet in your public library. It's better than filters (censorship)
Now, if you want to start your own internet cafe and have filters, that is your own business The marketplace and the quality of your coffee will decide.
How about you dump the gameplaying and answer a straightforward question?
Do you think a six year old child should have complete access to websites on coprophilia on a library computer?
Please note: Any response other than "yes" or "no" will be construed as an answer in the affirmative.