(And yes, no one has a right to be on the radio, but EVERYONE has the right, yes, via the first amendment, to be held to the same standards while broadcasting or be liable for the same financial obligations i.e. taxes no matter what political opinion they may express.)
No the First Amendment covers SPECIFIC issues VERY SPECIFIC ISSUES Speech, Religion, the Press, Assembly, and Redress of Grievances
What you are talking about with Equal Treatment Under the Law falls under another part of the Constitution/Amendments (That being the 14th Amendment Section 1 "Equal Protection Under the Law" clause though its not a clear cut and dried case) which again means ITS NOT A FIRST AMENDMENT ISSUE NO MATTER HOW HARD YOU TRY TO MAKE IT ONE.