Apparently, you're not sensitive to that stuff. Good for you. (Most people aren't, actually.) The small number of people who are sensitive to that stuff can have some nasty reactions to it. I'm sure they appreciate the warning. The rest of us can watch the movie in peace.
They didn't see any of the previews? Good grief, they were in all of them. The "Screen Slaver" was the main criminal in the movie.
Of course, let's cater to stupidity. After all, nearly half the population voted for Clinton.
Oh! I know! They should have a warning before all of the "Incredibles 2" ads! The theaters can tell those seated "If you're sensitive to the following preview, please leave the theater NOW!!!!"
And for the ones broadcast on TV, tell them "FOR GAIA'S SAKE, TURN OFF YOUR TELEVISION NOW!!!"