Well, some think the current policies are right - but not the leadership..... the leadership is tainted for many people e.g. for support of terrorists. A modern labour would have fresher people as leaders and would have been stronger against Brexit before the referendum. I think the leadership must now try and fight what is becoming Brexit Britain - which includes racism. I am sure Corbyn is doing this, but where was he at the referendum? The growth of right wing neo nationalism in the U.K. is partly his fault.
There was even "labour leave". My racist right wing brother campaigned on that. He thought it was funny helping labour for the first time in his life. An unbelievable alliance.
Then they have been caught out a couple of times with anti-semitism, which, whilst agreeing that Israel needs criticism, things like red Ken's Hitler comments and other dumb comments from others should never happen in a socialist party.
For me, a modern opposition doesn't include dithering about Europe or tolerating "labour leave" or old pensioners such as Red Ken. It needs a radical stance on Europe - that means keeping us as close as possible to the EU in case Brexit ends up being a right wing beano and a future generation wants to get back in - and the, apparently, good current policies being put forward by others than the Corbyn clique.