There is usually a difference between when people talk about "The Bay Area" (i.e., the geographic location) vs. "Silicon Valley" (i.e. a metonym for the tech industry in the bay area).
Psychedelics obviously were a big feature of SF and the bay area for a long time, but that's very different than saying they are an accepted part of the corporate tech world there.
At least we have a long list of cliches about Steve jobs and others tripping and starting companies dating back to the 70's and 80s! I don't think it's wrong to suggest both the Bay Area and SV's interest in those drugs started around the same time.
The Bay Area's psychedelic interest well predated tech capital.