The reason is in the opening line where the Daily Fail say:
"Senior Liberal Democrat MPs have escalated their controversial campaign to force the Government into decriminalising drugs."
The controversy of course is that Tom Brake has laid down parliamentary Early Day Motion 2404 which states:
"That this House notes the serious harm caused by drugs; recognises the need for evidence-based policy making with a clear focus on prevention and harm-reduction; and calls on the Government to establish an independent panel tasked with carrying out an impact assessment of the Misuse of Drugs Act 1971, reviewing the approach adopted by other countries, and making recommendations for reform."
It calls for an independent review on drug policy, it calls for recommendations to be based on evidence. Yes this may prove controversial as it may very be that evidence suggests that the safest way for drug addicts to get their drugs is through monitored medical sources rather than through street suppliers who mix all sorts of contaminants into their supply in order to get greater value for money. Many of these are more deadly than the drug use itself, that if proved by evidence may lead to a licensing of certain classes of drugs so that supply and quality can be guaranteed and so that life and support to wean off drugs can be monitored.
It may well lead to a revenue stream for government through licensing of such supply.
But the key element of the so-called controversial proposal is that it is evidence based. With such a knee-jerk response from the Daily Fail the one thing they don't want it the evidence to be looked into carefully as it may shake their world view.