Here's that moment again in this reaction video from emeryreigns (who also saw it as a disappointed Itagaki), it's 5m and 15s in, in case the timestamp doesn't work:
This happened just after Shimbori was promoting their KoF dlc (Mai and Kula). Before he showed the Itagaki pic, apparently Harada mockingly said to them, "adding no Kuma, only padded Kula?". Kuma, for anyone here who doesn't play Tekken, is a Tekken fighter. You could read that as him joking "You guys have no Tekken guest characters, I'm disappointed". Then he put up a picture of Itagaki, followed by another picture of Hayashi.
I don't think it's entirely right to assume or read what you want into what Harada did, at least not without a grain of salt. We'll never know his exact intention unless he tells us. Knowing the history of Harada and Tekken's relationship with TN/Itagaki and DOA, even if he meant it as "using Itagaki's disapproving face" (Itagaki always looks the same, how can you tell he's disappointed? lol), it was most likely all in good fun. Whatever he meant, the sheer irony is just hilarious to me. Harada was always seen as a rival or even enemy to Itagaki in the past by a lot of people, so seeing him bring Itagaki into the stream like that was just pure gold from that perspective, I don't know how else to put it. It was probably my favorite moment from the stream.
Aside from that, Harada was actually being pretty chummy with Shimbori and Mochi, and was encouraging all the FG developers to work more with eachother and help eachother out, so it doesn't make sense that he was just trying to maliciously kick them while they were down. Tbh, before the event I was crossing my fingers that someone, most likely Harada, would actually directly question Shimbori and ask straight up "What the hell happened, guys? We want to see DoA prosper too, so what's the issue??".
Even if Harada meant it to be an angry Itagaki face (and Hayashi face) in response to DoA6 getting screwed up (rather than joking about there being no Tekken guest), I think that's great too... someone had to say something about it, even if it had to be in a roundabout way like that. It was great that KT/TN was there to represent DoA, but it was clearly an elephant in the "room" (virtual room?) that they were the only ones there promoting a dead/zombie game.
Also interesting, and a bit disappointing actually, to watch that again and realize everyone was already laughing at the miraculous effect of when Shimbori put the picture of Tamaki up the the camera and the background of the pic went transparent, so I guess it was like Shimbori had turned into Tamaki, lol. So they were already laughing before Harada put Itagaki's face up.