What documents protects the right of citizens to hold meetings to discuss unpopular ideas?

I believe it would be the: United States constitution

To be exact, the first amendment of the united states constitution which give the citizens the freedom of speech.
This amendment protect people from discussing unpopular opinion as long as the discussion is not initiated to ignite violence toward other citizens.

the two sets of lines are :

and remember beauty,five-wits,strength,and discretion ,they all at the last do everyman forsake (to leave forever ) for after death amends may no man make,for then mercy and pity doth him forsake.(to leave forever )