I have no idea why your Primary physician has told you that. There should be no reason that you need to stop 2 weeks before. I imagine that the reason may have been that they thought you may be smoking the flower or vaping. If you consume it this way it can cause some sensitization of the lung that can make general anesthesia more irritating.
If you are using tincture this should not be an issue. After your surgery tinctures would be the way to go as well to avoid any lung irritation afterward, that can cause coughing, which you would want to avoid with hernia surgery.
Perry Solomon, MD