Does Labour want to be lead by someone who wished they had assassinated Margaret Thatcher in the 1980s?

I only ask because Labour List report that at the recent GMB labour Leadership Hustings John McDonnell when asked 'What were you before you were a politician' replied: ' is reported to have answered that:

'he was on the GLC - and that if he could go back in time and do one thing, he would visit the 1980s and "assassinate Thatcher".'

Labour List comment that 'The wisdom of such a statement really has to be questioned.' But then are they shocked or trying to stop John McDonnell from getting 33 nominations?