I don’t see how the message is anti-white. The claim seems to be that “free speech” has become something of a dog whistle. It’s certainly true where I am, and as a supporter of free speech I dislike the association!
If 'free speech' is a 'dog whistle' what would be a viable alternative to get the same ideal, without falling afoul of a shift in the 'dog whistle' goalpost?
It’s not as simple as that. You need to look at when someone comes out in support of free speech. Do they only use it as way to defend people who they support (for other reasons) and never in support of people they disagree with?