It's not at all obvious to me investors who bought their stock after they IPO wanted any of this.
The board and upper management together with their VC backers (they also gave Unity a significant loan to fund the IronSource acquisition which will be exchanged to stock in a few years) seem to be the main driving force behind this.
The only way most public shareholders can express their approval is by buying or selling stock and looking at the share price over the last 1.5 years they don't seem to approve that much.