Private sector vs public sector job?

I am not allowed to tell who I work for. Since I signed a contract with that organization.

I just got a new job and started 3 weeks ago in the private sector. How come they offer me more pay then the jobs in public sector jobs.

I get like $80.00 an hour for just siting around all day on a computer just printing out stuffs. Like labels, pictures and things like that.

But I do have a disadvantage to this job.

-My Employer does not pay taxes. Meaning I can't prove I worked there or not.

-No work unions or OSHA.

-Don't pay medical insurance

-Sign some contracts

Advantages:

-Get more pay

-Come in when ever I want

-Work less then 5 hours if you wish

-Easy task

-Get days off base of your performance

Honestly I like this job but

Why is it different I also did not have any of there job requirements. Why don't public sector jobs like retail, restaurant, teaching, media, and own business pay you good enough.