There's nothing about sympathizing with or even being on the left that prevents criticism of the left. The left is infamous for the amount of internal bickering, denunciations, and recriminations that go on.
That said, Huxley's critique of the left (if it can even be called that) didn't seem like one based on any left-wing principles or ideas. I really don't know where he was coming from on that. It really felt like it could have been written by some cheap right-wing tabloid. Maybe that's why it was so popular.
This is sadder still. You're saying you feel pacifism and anti-war sentiments are no longer a part of the left?
Huxley was critiquing Hitler and especially Stalin. Is that your idea of "the left"?
Sadly, the entire western world is just a lot more authoritarian than it was during Huxley and Orwell's time.