There is no 'danger' from 'not buying stuff from your dealer' anymore.
Dealers don't assault, endanger or attack random customers who just stop buying.
That's totally absurd, and that someone would suggest it - indicates that they are getting their information from Netflix/Hollywood films or something, not reality.
The vast majority of dealers are actually fairly normal people anyhow.
Doctors in emergency rooms usually have instructions to confiscate any illegal drugs they discover on OD-patients, but are faced with the very real dilemma of leaving the patient at their creditors mercy. This can cause real harm (as in "First do no harm") to the patient and their prospects of recovery or harm reduction.
But nobody is 'going after' someone who just decided to stop smoking something.