This is provably wrong. Preventative public health measures against for instance cigarettes and nicotine reduce uptake, reduce consumption and increase quitting. [1] In the case of smoking, this also cut second-hand harm/death from smoking. Similarly, preventative measures have first order and second order benefits for alcohol and other drug consumption.

Just giving up on those who show higher likelihood for addiction is a travesty. Failure to eliminate an addiction is no reason to give up reducing its harms, both to the person themselves, family and friends, and wider society.

[1]: https://tobaccocontrol.bmj.com/content/21/2/172