I think it is still taboo among most VC's and angels. Founders are supposed to be cookie-cutter stereotypes who fit a pre-established program. Your personality / public face can be "challenging" but not challenging, if you know what I mean.
An openly pot-head founder risks offending or scaring customers or buyers or later investors. It also indicates some who doesn't get the "performative" aspect of being a commodity founder: the expected degree of conformative role playing.
Wouldn't that be putting the company and its management in a very risky situation? Distribution of controlled substances carries much higher penalties than mere possession. If a disgruntled employee calls in an anonymous tip to the cops, they might end up with a bunch of heavily armed cops kicking down their office door. Not so great for productivity...