This is not a Niji defense. But Pomu left during the time NijiEN was ignored by Anycolor and right before Selen nuked the branch

Back then, 3D content aside Lazulight 3D debuts was not available so Pomu chose to leave simply because Anycolor refused to give her opportunities to perform as 3D idol fairy + the NijiEN concert cancellation. But after the Selen nuke, Riku realized that he could not let the branch implodes itself to the public so he "patched" it by spamming 3D content and heavily promoting it to the japs

Mint basically has outdated infos that it is easy for sisters to debunk. If you want to diss Niji in an effective way, use the grads and dramas post-Selen, because it's clear Anycolor only chose the temporary option and basically try to milk every last drop of relevancy until the reports proved otherwise. If NijiEN revenue continues to decline even when BtB revenue is accounted for, Anycolor will start doubting its value, and that's no good for NijiEN