I can only speak anecdotally to my group I met with prior to leaving Tokyo, but we did have some minority members, we had a black member, born and raised here but parents weren't, and he seemed to be treated basically the same as most anyone. Newcomers would often be surprised he spoke Japanese until they found out he was in fact Japanese. We also had a couple half-Japanese returnees but they did look very Japanese. They're not very keen on US military/soldiers in the country, but they don't seem to paint all USians with that brush. I myself am from the US, even if I haven't been back there for 20 odd years.

The party's public positions are very inclusive as far as Japanese politics go, and, while I realise it isn't related to your topic, is the most active about feminist and LGBT issues. Which is, admittedly, a very low bar in Japanese politics. They're against the anti-Korean racism that pervades most of our conservative parties, and are the only party that really seeks to avoid historical revisionism in regards to Japan's own war crimes. In fact, they want that to be taught more than it already is. They tend to advocate for distancing Japan from the US and partnering more with other Asian countries. Which, until very recently, included China.

I have a lot of issues with the party still, but there's no denying it is the best of our big political parties. Which is...again, not saying a whole lot.