Not a good take. We absolutely do need to justify whatever degree of violence we think it will take to replace capitalism -- how else are we supposed to get popular support for it? Even the "we shall not make excuses for the terror" quote immediately excuses the terror by pointing out how it's a response to the violence of "the royal terrorists." The "there were two reigns of terror" quote does the same. Justifying violence also clarifies which types of violence are necessary and which are excessive, which is another key part of building and keeping popular support (see Mao separating the PLA from the warlords by mandating that they pay for supplies from peasants rather than just stealing them, see the Red Army's punishment of sexual violence during WWII).

And that's in a revolutionary context. In a post-revoutionary AES state there's even more rationale to justify whatever violence we think is necessary to maintain that state, as the threats it faces are less imminent and it has more resources and time.

That is a good point