Final Panel: "then they stole this manwa on us"
Okay, the dubious phrasing (ie, "on us") aside, the appropriate statement would be "stole this translation", as the translation team presumably doesn't have the rights to the manwa, nor are in a position where they could reasonably criticize such "theft". Side-note, if we're going by proper [legal/dictionary] definitions, theft requires the actual removal of the original element from the source to be classified as theft [ie, theft takes something away from someone else], so to be accurate it'd be referred to as exploitation or infringement instead. Backing up a step, it's just bizarre for someone who is themself engaging in "theft" [read: unauthorized reproduction, which falls under copyright infringement rather than theft] to criticize someone else for it.
All the moreso when they're (unintentionally, presumably) claiming rights to the work they've infringed, when discussing someone else infringing upon their reproduction. Not meaning
any implications towards the translator from that, just saying it's really a head-scratching statement, as it's presented. In other words, I'm just poking at the phrasing and presentation for being so weird, rather than at any of the sentiments or actions of the translator- rather, it seems reasonable to me for them to have some say. Or to put it more clearly, I'm saying it's fine for them to decry unauthorized reproduction of their translation, but their current phrasing kind of undermines the legitimacy of them having any right to make such argument.
Again, not at all intending to argue the ethics of the matter, just pointing out flaws in the vocabulary and logic.