If they tell you the company, what's stopping you from turning them down and going directly to the company? I'm pretty sure that's the main reason they don't tell you the company.
To me, the recruiter is representing the company. If they're reaching out to me, I'd like to think I already have an "in" with the company. Why would I circumvent that and go in alone?
Because the recruiter gives names to the company of "here are the people I gave your contact info to" and the company makes sure that those people only go through the recruiter.
I've had recruiters tell me right upfront which company they are dealing with.