Yes there are shit employers - but we have ways of keeping bad employers honest - impact on public image, H&S legislation (and fines), standards, auditing (fire, food, building WOF), industry membership bodies, regulatory bodies, etc.
What do we have to keep bad employees honest? I solidly believe in win/ win situations. Make it work for both. If an employee is ill suited it helps no one not being able to get rid of them within 3 months.
Teach a man to fish philosophy - overly protecting employees does help them (trial periods etc, not exposition). A good employee can get a job anywhere tomorrow and the employer know it.