Not a bad strategy on RFK’s part to get anti-Trump support before switching/adding to that his inevitable attempt to get anti-Biden support.
He’s not trying to get the anti-Trump vote with this. He’s trying to get currently ambivalent Trump supporters away from Trump. This could be a big problem for PDJT if RFK Jr. starts peeling away those voters from Trump’s base.
And maybe this is his plan. Maybe he’s trying to help Biden.
Perhaps if Trump didn’t give his voters a reason, such as, say, continuing to extol his great vaxseem, to be ambivalent about him, then they wouldn’t be ambivalent.