Ah, the old "No true Scotsman" logical fallacy
Right now, criticism of Jeremy Corbyn and his handling of Brexit seems to be coming from everyone apart from his immediate cadre - including most of the parliamentary Labour Party and Labour Party membership. Sure you can dismiss all of these as part of some Blairite faction but they seem to outnumber the "true" Labour loyalists.
There are, but I've not criticised Jeremy Corbyn for being antisemitic.
There is evidence of antisemitism within the Labour Party but it long predates Jeremy Corbyn's leadership and similar focus may identify similar cases in other parties.
There is a big difference between New Labour and the Conservative Party. If you need evidence of this, just consider all the changes that the Conservative-led coalition made in the name of "austerity" to make the rich richer and the poor poorer.
Principled can be a positive, but principled and inflexible results in dogmatic. Jeremy Corbyn is undoubtedly the latter, he seems impervious to new information or fundamental societal changes and his views and policies are invariant.
It's not the default but 2/3 of Labour voters voted to Remain and recent polls put that number close to 3/4 so it's a minority view within the party and one where there is good evidence that it is driving away support (such as the YouGov poll which indicated that Labour would have been clear winners in the recent European elections had they adopted a Remain or even second referendum stance).
It's true that Jeremy Corbyn seems to want to establish a workers' utopia but that would require the UK to pretend that globalism doesn't exist and/or to disengage entirely from it.
It also flies in the face of the evidence that immigration from the EU hasn't driven down wages (but then again, Jeremy Corbyn appears impervious to any facts that challenge his views).