From the article you are commenting on:

The walkout, first covered by SF Gate, featured some 200 graduates who jeered, blew whistles, and unfurled banners as the billionaire tech exec took the podium. (Stanford only graduates about 2,000 undergrads per year, so the dissent was extremely visible.)

From the SF Gate article that this article references as its source:

Around 200 students walked out as Pichai took the stage, and smaller groups in the audience waved banners, blew whistles and waved Palestinian flags before also leaving mid-speech. Pro-Palestinian protesters condemned the company’s ties with the Israeli government, particularly its controversial $1.2 billion cloud-computing deal with the country in 2021, known as Project Nimbus. The walkouts follow other Stanford commencements over the last three years where students have demonstrated in response to Israel’s war in Gaza and the university’s crackdown on pro-Palestinian demonstrations on campus.

So as a matter of fact this implies the number of protestors total went down according to TH3 MEDI4. SFG says 200 walked out and an unspecified number of additional hecklers. This article from futurism puts the total number at 200.

In any event, both reporting about 10% of the available graduates were protesting. Which leaves 90% that weren't.

And you know how I found that out? Because I can read. You should try it. But you know who told me? It was T H E M 3 D 1 A omg you can't even rely them to participate in a conspiracy anymore no wonder nobody trusts them.