It's not a high horse to find the rules of the company you are working for (and the nation/state you live in) to be considered something that shouldn't be violated.
I sincerely hope that you fail your drug test and do not get the job. Even if you smoke, it's not like you all of a sudden applied for, and got a job that mandated a drug test. You knew of the test at the latest when you interviewed, but most likely when you applied. That isn't a high horse, that's simply not wanting someone who willingly, intentionally violate the rules to be getting a job. You do a drug of any sort, you face the risks, which in your case would be not getting a job.
And your father is just as bad, enabling you.