I don't think there's any logical conflict. They stated that they thought the type of prion they were handling couldn't infect humans. They see now they were likely wrong.
I don't read any implication that they see they were likely wrong. According to the article, he actually refused to comment on the French cases and said their own lab "only use mouse-adapted sheep prions, which have never been shown to be infectious to humans." Not even "_had_ never been shown". It seems unclear what his view is.
It immediately goes on to talk about their own discovery 10 years ago that prions could be spread through aerosols which "totally shocked" them and might "warrant re-thinking on prion biosafety guidelines" but that seems an entirely separate thing from the decision to use only sheep prions for research.
It immediately goes on to talk about their own discovery 10 years ago that prions could be spread through aerosols which "totally shocked" them and might "warrant re-thinking on prion biosafety guidelines" but that seems an entirely separate thing from the decision to use only sheep prions for research.