There is a difference between contributing nothing to society and doing more harm than good overall.

The former is just wrong in the case of Meta, you don't need to look far to find many of their contributions. The latter is debatable, but it is not what you said.

There is also a difference between the company as a whole and the people working for it. Their "very fat salaries" can let them support noble causes, or not, they are people, in all their complexity, not just machine parts.