There is quite a bit of political speech measured to silence the opposition. Examples are not hard to come by. Should they be outlawed too because their intent limit the marketplace of ideas?
Moreover, because setting rules will inherently be a political process are you comfortable with, say, Donald Trump and/or a Republican congress setting those rules? Or politically lopsided state legislatures of Texas or California?
If you are talking about universities, I spent too long on campuses to trust university administrations to do this in any kind of fair way. Again, would you trust Liberty University to set speech rules that are fair?
The setting of rules by the powerful, who, make no mistake, will set these rules, will inherently disadvantage minority viewpoints.