If it's provided because of its benefit to the employer, it's not taxable (same reason company computers are a business expense and not a taxable perk to the employee).
The logic is that the company gets benefits from providing meals that exceed the costs, e.g. shorter lunch breaks since employees don't even have to leave the building. And given that meals can be provided at scale for under $10/head, then even shaving 5 minutes off a lunch break is worth it at Big Tech compensation levels. There's also benefits to having employees eat more meals with other employees, and thus some work gets done over lunch.
The logic is that the company gets benefits from providing meals that exceed the costs, e.g. shorter lunch breaks since employees don't even have to leave the building. And given that meals can be provided at scale for under $10/head, then even shaving 5 minutes off a lunch break is worth it at Big Tech compensation levels. There's also benefits to having employees eat more meals with other employees, and thus some work gets done over lunch.