No one is perfect nor should be expected to be. By being allowed to share the link, people were able to correct him, and he and the general public, became more knowledgeable as a result.

People being free to share wrong ideas has social value.

And no, sharing a false or premature report is not extremism. Demanding censorship is.

I mean, he deleted the tweet after it was shown that the article it shared was without merit. What else do you want?