Yea, that was definitely a bad look not acknowledging Min Min's Chinese representation, but don't place any of the blame on the Patron who asked the question. The reason this even happened was partially due to me not reading the Patron question correctly (I subbed their use of "will we see more Black/Brown skin characters from Nintendo" with "will we see more minority characters") as the question was originally asking for a lack of a certain type of representation in Nintendo/Smash. I subbed in "minority" as shorthand for the question on-the-fly without realizing what I had done, and sadly did not catch that I had misrepresented the question and Min Min. I was so focused on making the point about lack of a certain type of representation that I fell into this pitfall of saying something that devalues one type of minority over another. This wasn't the intent, but it still illustrates a problem you and others rightfully called out. More representation in general is a good thing, and we should have praised and addressed the importance of the inclusion of Min Min rather than being so focused on Black/Brown representation.
As for the nuance in how Japan deals with racism for your first point, I get their is a history there as you explained with their position and philosophy. However, I will say ignorance is no excuse, even when it comes to Nintendo/Japan/other countries. Nintendo/Japan is absolutely aware of racism and the specific racism we bring up against Black/Brown skin people, and NCL is ABSOLUTELY made aware of issues by Nintendo of America (and other Nintendo subsidiaries), we have documented instances of them impacting game development as a result of input from them about how games will be viewed outside of Japan. This goes beyond merely localization changes for regional versions in some instances, such as changes that are on the Japanese level, too (see Tokyo Mirage Sessions ♯FE Encore only being based on the original's Western version, for all territories the Switch port released in). Also the recent removal of Mr. Game and Watch's offensive imagery related to racist depictions of Native Americans. The point is that people need to keep holding these companies accountable and educate them. Obviously anyone can be ignorant of something, but once that's brought to light and you are shown why a viewpoint is considered offensive, what you do next matters the most. If you don't change and respect the views of others, it shows your prejudice and unwillingness to change and thus are deserving of the backlash coming your way. If you change for the better and show compassion and understanding, that is deserving of praise.
So my apologies for the poor handling of our discussion on Min Min. I hope the rest of the conversation proved more productive and useful towards arguing for the better representation of marginalized groups, as that was the only true goal I had for the topic.
Edit: Want to also add that it probably was also a big miss to not celebrate Min Min's Chinese heritage from the perspective of an American because it would be a positive counter to the racist rhetoric utilized by idiots in this country when referencing the current coronavirus/COVID-19 pandemic which has caused undue backlash and hardship for Chinese-Americans and nationals.