If you refused to hire even occasional pot smokers (or take investment from them, or invest in them) in the Bay Area, you'd have a really hard time. (This comes up with federal government related contracts and staffing.)
I am not saying that there should be hard rules. Just that there is a stigma there, and that it is there for a reason. Would you invest in a company with technical founders who got high every day?
Pot wouldn't be a factor in my investment decision; it would depend on the quality of work they did.
I don't think drugs are incompatible with being a responsible and productive person. There would be downsides to high profile drug use, like what happened to Sean Parker at Facebook, where presumably there was fear that the LPs in various investors would raise issues.
People can be useless fucktards with or without drugs; people can be productive with or without drugs.
I don't think drugs are incompatible with being a responsible and productive person either. I think that they are negatively correlated with being a responsible and productive person. I think a search will turn up a lot of evidence to support that.
Pot isn't the worst thing ever, but it isn't going to help you start a business or become a great programmer. While you are high, you will be worse at reasoning and your working memory won't be great. This makes it harder to write code. There is also a legal risk, justified or not.
Drugs are a frustrating topic to debate. On one side there is a huge amount of misinformation intended to scare people away from drug use. Then, in reaction to that and coming out of the cognitive dissonance of millions of people doing something that they know isn't good for them, there is a ton of 'pot is good for you because it comes from the earth' bs on the other side. I think people on the internet (and apparently on HN) tend to be in the latter group, and I feel like it is worth pointing out the downsides.
I wrote my mathematics PhD thesis while smoking pot to relieve some terrible back pain. Cognitively, it helped me on occassion to break through barriers in abstract reasoning and creativity. You might have had a bad experience with drug use, and I do sympathize, but please spare us the sweeping generalizations.