I agree that the burden of proof is on creationists if they want to positively assert that God created man, but plenty of anti-evolution activists limit themselves to the narrower grounds of just claiming "evolution is only a theory, burden of proof is on the evolutionists". Yet they tend to get called "denialists" in that case, also. (Though I agree the evidence for evolution is much more mature than the evidence for AGW.)
The mistake you're making is that you're presuming an equal burden on the so-called "denialists" like they have to prove there isn't global warming. They don't. AGW is an hypothesis. The burden of proof is on it. This is the same mistake creationists make when they take any missing, incomplete, unclear or contradictory part of evolution to mean that God exists and he created Man.
If nothing else the CRU email hacking should give everyone cause for concern at the subversion of the scientific process. Efforts were clearly made to deny access to raw data, generally be obstructionist and the failure of respected journals like Nature not to enforce their policies of, say, the publication of raw data. Or the IPCC admitting their Indian glacier claims weren't based on anything other than a single unfoudned comment in a years old newspaper.