In both meat eating and driving those activities have inherent harm, eating meat will cause animals harm, driving a car will cause pollution and release of GHG.
The harm of the drugs trade (on a societal level) is _due to its illegality_ I.e. it is run by criminals.
Regardless, it is absolutely not immoral or unethical to consume drugs. What is immoral, is imposing the negative consequences of prohibition upon society because of your particular moral code. You want to lock people in a cage at the end of a gun because you disagree with the choices they make for their own bodies. It is authoritarian shite of the highest degree.
Are you sure people who want to keep heroin, meth and coke illegal are doing it because they want to legislate morality and control others bodies?
Or is it because they don't want to have to deal with the negative effects that these drugs have on their community.
Criminalizing them hasn't been the solution, but decriminalizing them will not make things that much better either...
From my perspective, most of the bad effects of those drugs occur due to their illegality. Meth, heroin, cocaine, etc. is pretty fucking dirt cheap to produce. The impurities and high costs and unknown doses and burdens to the carceral system are what impose the bulk of the costs to society.