They're trying to make the whole movement look dumb by proxy, or that anyone who joined the movement is dumb because they're following a dumb guy. The public PR angle is that only a dumb stupid babbling person would deny the goodness that Amazon does for its employees and try to organize a walkout.
I think it's interesting the contrast with the SVP who said he let his emotions got the better of him. If the union guy says something not-smart, he's dumb and the whole movement is dumb. If the SVP says something not-smart, he was just trying to protect the workers.