If there is going to be a debate, every candidate in the race should have a say. The attempt to muzzle them, and himself--when he was paying to assure that fairness--should prompt outrage in anyone.
The others were there because Reagan wanted them to be able to speak their piece.
It is the sad absence of that same sense of fairness today by those from the shoutdown school of political discourse (most, but not all, Liberals) which stymies rational debate.
As for the tactic of shutting up the opposition by shutting them out, well, that's something we see from the current Pres__ent and his cronies.
It's only natural that Reagan's sense of fair play resonated with Americans.
You are absolutely right.