Elon thinks an exercise of free speech (people voicing opinions to advertisers) is a violation of free speech.
I'm not sure he could pass a Civics 101 class.
EDIT - who is "they?" Very easy to play the victim when you can't define whoever is supposedly trying to suppress your speech.
These advertisers are not exercising free speech, they are being pressured by activist groups. I suspect they are even being blackmailed with the threat of a boycott.
You can read, so why don’t you read what Elon posted.