Yeah, at least he should take down also the credit card fraud boards, they are doing real harm.
Since the argument is gone, i see no reason not to do that.
I'm not sure if this is the right approach. By doing such things, I think they actually are helping the white supremacists. They won't think they did something wrong there, they think they sold legitimate shirts just like Gay Pride(or whatever) and got shutdown for their opinion, which confirms their idiology/conspiracy theories/hate.
I think the answer for alt right is more debate / speech /facts, but e.g. instead in germany they are just passing new laws for censoring facebook and violators even got search warrants. Again wrong way imo, deleting their Facebook post doesn't equal changing their opinion, it rather confirms their idiology.