The issue isn’t state vs federal law, it’s that alcohol filters out of your body in around 8 hours so I can drink after work and on the weekends and I’m fine. Anything containing THC, on the other hand, will show up on a drug test for about a month and my company doesn’t care if you had it a day ago or three weeks ago, a positive test is instant separation of employment.
I don’t think you understand what I’m saying with YET. When the federal law inevitably changes the laws will be similar to DUI. They won’t be able to stop you permanently from partaking, just give you a window you can’t imbibe.