They would likely accept it if it came with strict requirements that the addicts must also undergo counseling and engage in a job/housing search if they are currently unemployed or homeless. It’s not punishment that most people on the right want, it’s personal responsibility of which being punished for criminal activity is just a small component. If the addicts using these centres were demonstrated to be making real progress towards getting clean and reintegrated into society then the vast majority of conservatives would support them. The opposition is to a policy that is essentially no different from legalizing opium dens that support only the habit without requiring treatment.