If campaign material was not capable of changing the minds of the electorate, nobody would waste time effort and money on it.
Free speech is valuable and worth defending specifically because it has the potential to change minds, not just because people like the sounds of their own voices.
(For the recent US election, people also point to Musk buying Twitter and getting his president of choice and saying this demonstrates why Musk is smart and $44bn was worth it, so are you sure it wasn't won by the biggest spenders?)
Free speech is valuable and worth defending specifically because it has the potential to change minds, not just because people like the sounds of their own voices.
(For the recent US election, people also point to Musk buying Twitter and getting his president of choice and saying this demonstrates why Musk is smart and $44bn was worth it, so are you sure it wasn't won by the biggest spenders?)