The 'centre left' have been in control of the Labour party for nearly two decades, during which time, to the best of my knowledge, the full-blooded left have never thrown all the toys out of the pram and tried everything in their power to overthrow the leader and replace him with their preference (Blairites vs Brownites I guess is the closest to this, but it's not like Brown, in practice, was very much different to Blair).
Now that the left does have control of the party, the centre-left are doing just that. Every single one of their arguments (we have to have a debate with the Tory party, we have to appeal to the voters, we have to remember the people who need our help) have gone out of the window in favour of trying to overthrow a democratically elected leader to get what they want, with apparently no concern for the fact that it's destroying their party credibility and can only end with Labour being out of power for the forseeable future. Calling them Tory-lite isn't intended as an empty insult; they've demonstrated over the past two months that they really do sit closer to the Tories on a wide range of issues than they do to the actual left wing of their own party.
Did Corbyn vote against his conscience just because Blair was leader of the party? No. So why should the centre-left now act in blind loyalty against their convictions?
If the centre-left of the Labour party are Tory-lite, then perhaps that's what they believe is the right path for the country. What I don't like is the insinuation that each and every one of them is somehow betraying their principles or selling out by being 'Tory-lite'. It's delegitimization of their views.
Yes, Corbyn was elected on unprecedented support from his base, and he is still extremely popular with them. But that core of support is not necessarily identical to Labour voters at large. I think the expectation that Labour MPs who are centre-left should suddenly become Morning Star subscribers because Corbyn was elected is unrealistic and honestly unfair.