Upon rereading as an adult, I find it much less anti-totalitarian than it was presented in school. Sure, there's bits of Orwell's usual concerns, but the presentation of the revolution and the persons working for the revolution is almost 100% positive. It is definitely not a rightwing book.
Certainly the porcine vanguardists are subjected to ruthless critique, and are rendered indistinguishable from the prior, slaveowning ruling class--except that their system had higher productiviety with lower labor costs (i.e., food for laborers) than the system that it had replaced.
A decent allegory for the Soviet Union, of course, though bits are commingled here and there, incomplete in other respects (the Trotsky character is not obviously murdered, say), or presented too schematically for anything other than satire.
My edition is old enough to include the subtitle "a fairy story," which was redacted by most US publishers during the cold war--an oddly orwellian bit of editing. Not sure what to make of that, though the introduction suggests that the object of the critique was also the practice of representing fairy.
Fairly obvious the another object of critique is the system that is replaced by the revolution--though this was not emphasized when I was instructed on the correct interpretation as a kid. No surprise there, I suppose.