There were liberal billionaires holding purse strings about college students protesting the killings in Gaza.

What do you mean by the verb phrase “holding purse strings about” here?

I know what holding purse strings means: one controls the money for an operation hence gets to decide.

But what does to mean to “hold purse strings about” these protests? You’re saying they were funding them? Or funding reporting? Or funding the schools? Or what?

What’s “about” mean here?