Because ISPs are not regulated by any federal agency. The Internet is still in its Wild West phase (and I hope it remains that way).
ISPs have Acceptable Use Policies (AUPs). Sites can only be legally terminated (per contractual agreement) when they violate those AUPs. If someone's on there spouting anti-American bullcrap, that's not grounds for site termination.
I'm not wild about the current arrangement, but consider how screwed up it'd be if we actually started shutting down sites based on errant content. You can bet your butt that the Leftists' first order would be to shut down Free Republic based on a few errant posts.
We can.
The one big exception to the 1st Amentment protections of "free speech" has to do with advocation and/or encouragement of illegal activity.
NAMBLA has already been slapped down once for their "speech" regarding recruitment of young boys into butt-banditry.
Links Of Interest
http://www.truthusa.com/LinksOfInterest.html
We certainly can, and if not legally it could be done covertly. My guess is that we let them do their thing and try to gather intelligence from it. Same reason the Brits didn't stop Lord Haw Haw, or the Germans the BBC transmissions to France.
ON THE NET...
http://members.hostedscripts.com/top.cgi?user=ila000
meshawir@hotmail.com
http://meshawir.freewebspace.com/
meshawir@hotmail.com
http://www.hostinganime.com/meshawir/
ma7jooob@yahoo.com
http://www.hostinganime.com/meshawir/english.html
http://meshawir.freewebspace.com/
meshawir@hotmail.com
http://www.google.com/search?q=%22hostinganime.com/meshawir%22&hl=en&lr=&filter=0
http://www.google.com/search?q=%22meshawir/english%22&hl=en&lr=&filter=0
http://www.google.com/search?q=%22meshawir%22&hl=en&lr=&filter=0
http://www.google.com/search?q=%22meshawr%22&hl=en&lr=&filter=0
http://www.alqa3edah.q6.net/
http://www.n66n.com/up/pic1/AAJJ0.gif