Earlier quoted context omitted.
And you are talking of current polling. I believe you will find that in Corbyn's hayday the polling was suggesting he would sweep labour to power.. but with the wrong politics. Hence being pro Palestinian was turned (in the bbc reporting) into "anti Semitic".
Corbyn failed because he was a bad politician with extreme views. It was Corbyn not the media who covered him that chose to defend every antisemite they could find. If anything the media was too nice to him(the media is often too worried about false balance you get similar things with Trump). It's entirely unsurprising that he lost what would have been a labor victory without him
I don't think there is a single point there that is not an assertion. You should become a BBC reporter.. although their assertions are usually reported as "xxx said..."