The two investors with whom Zhu seems to take issue were born and raised in South Asia and Turkey, respectively.
Zhu was replaced by his co-founder (who supported Zhu's firing) who is of East Asian descent.
Zhu believed "the company were too focused on sales and money at the expense of altruistic goals". Excuse me? You're running a company with other peoples' money at stake with the express understanding that you will seek to maximize their returns.
Zhu was the one who publicized the LSD incident (which was NOT a microdose, as he admits) via his contact with a reporter. The board actually tried to intervene. Imagine finding this out as an investor. Now all your company's current and potential customers, partners, and investors know that you've got an Adam Neuman type at the helm. That's got major potential to harm investors.
Ultimately, this reads as an egoist who can't sufficiently control his impulses. It's a wonder he wasn't fired sooner.
Separately, much of the reporting on this has been emblematic of the sorry state of journalism. This article, for example, bends over backwards to draw tenuous connections between racial bias/identity politics and Zhu's firing. Truly shameful.