Not seeing how that makes him as bad as Johnson and a majority tory government.
Because insofar as the single most important thing to happen to the UK since the second world war, they both want the same thing - Brexit - and both have worked tirelessly to ensure that any attempt to prevent it founders.
Indeed if you think about it your worries in regards to workers rights and so on being lost once we leave the EU, do you really think both Johnson and Corbyn are as likely to legislate to remove the current rights?
Whether or not workers' rights are preserved or not is a secondary concern compared to the damage that Brexit will inflict on the UK. Workers' rights are nice, but if economic contraction results in hundreds of thousands or millions being out of work then they're a rounding error in the broader scale of things (and that presumes that nationalisation and transfer of ownership to employees doesn't have negative economic consequences).