The PAP sues its opponents for defamation. Has your government ever done anything worse?
You mention one small piece of the pie of justice: political free speech. What about property rights, banking law, business law, immigration law, tax law, criminal law, etc? I think you need to show a much broader pattern of abuse to say the judicial system isn't fair.
I'm actually a libertarian. Its taken some time for me to reconcile that with my support of Singapore. Basically, I believe Singapore is more free than most Western countries although sometimes in different ways.
You can quibble about minor issues, but in my experience the government delivers good service, safe streets, a growing economy, and opportunity to the vast majority of Singaporeans.