Based on my experiences watching History Channel shows...in general they are biased towards the left wing. I can give you many examples.
As for the actual drug show which was produced in 2001 BTW - I heard snippets and my impression is that it was a slickly-made overtly non judgmental presentation. The overall tone seems to be...well... we've been doing drugs for thousands of years...let's keep doing them and not be so uptight. The tone is what I object to.
In other words, your opinion is based on your feelings or your emotional reaction to the program. What facts did the History Channel get wrong?