Yup, a disgrace all round. And it wasn't just that he's a vocal socialist, but that he'd been one all of his long and dedicated career, and had proven to stand by his morals rather than by what might seem popular, or profitable to him personally at any given time, like the rest of his colleagues.
I'm under no illusion that Corbyn on his own would have been enough to turn this country in to a full blown socialist one or toppled capitalism, but the fact that they were scared enough of what he could have done (like you mentioned the renationalisation, but also putting money back in to the existing national services like social and health that the rich have been stripping for profit, and taxing them and their corporations significantly more) proves just how big of a threat they really saw him as (and he really was, even in spite of the smear campaign he came so fucking close. For the uninitiated, I think his Glastonbury appearance - I linked to my favourite part which still gives me chills but the whole thing is worth watching just for the sad reflection over what could have been - really made them realise they could never ever possibly even come close be that kind of genuinely popular).