This one really annoys me. Yes, people care more about people who look like them, and certainly those who are closer and where war is less common. Same reason predominantly Muslim diasporas in the west care about Palestine a lot
This particular refrain is one that's worth examining from the lens you're dismissing. Under what frame is "war less common" in Europe (or even "East Europe")? An extremely narrow one at best, IMO. A large proportion of pro-Ukrainian propaganda also outright contradicts this notion by referencing historical acts of Russian aggression.
I do concede that this is the least relevant point though, the similarity one is much more significant.
I don't think that's true. It's true the Muslims I know care about Palestine. But, for example, nobody cares about Uyghurs, who are Muslim. I don't know any Bangladeshis that care about the Rohingya, even though they're at least closely related to Bangladeshis (and "look" the same and speak a closely related language). My impression, being part of this "diaspora," is that the common support for Palestine is more about shared animosity against Israel. This animosity is partly just anti-Jewish, but also partly anti-Anglo-meddling, insofar as Britain was instrumental in enabling Jewish repatriation of Israel, and the United States continues to support Israel.