The real problem is the Misuse of Drugs Act being drafted the way it is. The categories of drug are meant to be in order of danger to the user. That's a scientific question. The government is meant to reassign drugs in the light of the latest scientific evidence, The advisory panel is to tell it what that evidence means and how the drug should be categorised therefor. That's why cannabis was downgraded to category C.
The Daily Mail exists to tell government what makes a good headline and what the beliefs or prejudices of middle England are. It runs a campaign to have cannabis as class B. The government plays to that, knowing that, in reality, the courts will sentence as they have done whatever category it's in.
If the Act had made all illegal drugs the same, without categories, we wouldn't have this problem. Nutt is correct. Strictly, the government has acted wrongly since it has no evidence (it hasn't claimed any, you note) to justify the change and has gone against its own committee which has assessed the evidence Unfortunately that's politics..