The last few paragraphs are also what grabbed me the most.

Thus, once they themselves became the ruling class, these revolutionaries lost their revolutionary quality and turned round to oppress the exploited masses; this was the inexorable law.

I can see how bourgeois revolutions would turn out that way, once in power, the bourgeoisie can start exploiting people themselves through financial means (more effectively).

But such can never be the case with the proletarian revolution and with the Communist Party.

I agree with the interpretation that this is what we must ensure after a successful revolution. At the same time, I also interpret it in a way where the proletariat generally speaking isn't a class that can exploit/exploits another class, so the members of the proletarian ruling elite would transition to being a class of ruling bureaucrats before they start exploiting the proletariat anew.

The proletariat is able to build a strictly organized and disciplined party and set up a centralized and at the same time democratic state apparatus, and through the Party and this state apparatus, it is able to lead the masses of the people in waging unrelenting struggle against all corruption and rottenness and in ceaselessly weeding out of the Party and the state organs all those elements that have become corrupt and removed (whatever high office they may hold), thereby preserving the purity of the Party and the state apparatus.

This, I feel is a very important statement to take to heart. We, as revolutionaries need to not only constantly improve ourselves (through self-crit among other things) but also the vanguard party and proletarian state, to ensure it doesn't removed into class oppression (of the proletariat) again. It's also interesting to consider this statement in the context of Xi's anti corruption purges.

I can't wait to see how the text continues from here.