I know it's a zombie thread, but I definitely think this could be a relevant Dis topic. Over a year later and there are now way more THC products legally available all throughout the U.S. They are becoming very popular among people who would normally never have "gotten high" in their life. Grandparents are taking gummies. Anyone over 21 can drink seltzers in bars. Lots of people are traveling with their vapes. Etc. It's becoming fairly commonplace and looked upon as being similar to drinking a glass of wine or having a cocktail.
This is my personal feeling as well. If you are allowed to consume alcohol (while NOT working), then I don't see any reason to ban another legal substance. It used to be that marijuana was included in the employee drug screen because it was illegal and alcohol was not included because it was legal. But if they are both legal, you should be allowed to consume them as long as you are not under the influence while working.
My company recently was updating our employee handbook and had to figure out a way to word our policy. We do not see any reason to prohibit the use of products with THC, but our employees work at various hospitals and surgery centers (many of which require a drug screen that includes cannabinoids). So, while we would not fire someone for using a legal cannabis product; they may be excluded from working at a certain site if they do not clear the drug screen.