He’s denied that he wrote the newsletters. He’s said that he didn’t pay close enough attention to the content that was going out with his name on it.

I haven’t seen any definitive proof to the contrary.

He’s disavowing the content. Content that he said he didn’t write and that nobody seems to be able to prove that he did.

This wouldn’t be the first time that circumstantial evidence supposedly “proving” something would turn out to be wrong - (see Wiener and Yfrog).

This wouldn’t be the first time somebody distanced themselves from comments made in the past - (see RoPMA).