1. They DDoSed PayPal, Swiss bank PostFinance, etc. Probably caused millions of dollars in damage.[1]

2. They illegaly hacked into a company's servers, stole and published confidential data.[2]

3. They are part of a community that mostly hosts child porn, pirated material, etc.[3]

I challenge anyone to give me a single reason (apart from the technical prowess) that would justify any sort of admiration... Seriously.

[1] http://arstechnica.com/tech-policy/news/2010/12/4chan-rushes-to-wikileaks-defense-forces-swiss-banking-site-offline.ars

[2] http://arstechnica.com/tech-policy/news/2011/02/anonymous-to-security-firm-working-with-fbi-youve-angered-the-hive.ars

[3] http://boards.4chan.org/b/