I don't know if you are genuinely curious but this question is getting kind of old. Every time a company does layoffs, somebody asks, "why does an X company need X number of people?". Every opening has a purpose. No company hires people for fun, and unless you are a company employee you don't know all the different areas, projects, and support staff a company needs to run when they are actually a business trying to make money.
It is a genuinely curious question. I haven't seen the abundance of "Why do they have so many employees" question as I'm new here, and that just seemed like a lot of employees to have if they can just lay off 1/3rd of their workforce overnight.