If a foreign student wants to leave a war zone, they should be allowed to leave, regardless of color or gender. So let's get that out of the way first.
I think there's a lot of sensitivity among people of African heritage regarding Europe in general. Whether it is Slavic Europe or some other part, Europe has a history of discrimination and, often, outright animosity against Africans.
Then again, so does Asia, along with other parts of the world. So there's that.
As for this point about the behavior of African rulers, keep in mind that almost every African nation was carved by European-drawn boundaries, and the various ethnic conflicts were egged on by European colonialists long ago.
Most of the problems we see in Africa are direct results of colonialism, which stripped the various nations there of many skilled people and created working "opportunities" in order to promote the extraction of minerals and wealth from their lands.
Meanwhile, Africans have had to deal with savage attempts at making them seem like second class citizens for hundreds of years. Often times, they've even been called a second class species by Europeans and Americans.
I would argue that even if Black writers are being too sensitive to the plight of African students, and I question that premise in the first place, they should be allowed to err on the side of their sensitivities.
There's no doubt that Putin is a jackal, and what he is doing is wrong. But we should never look at everything from a black and white lens. There are gray areas, and examining a wrong from within another wrong is okay, too.
As someone who works frequently with Ukrainians (over Zoom), I am rabidly cheering them on. I have never seen any of them exhibit any racism. But elements of racism exist in all European societies. It's a stain that has haunted European and American history for a long time.
So in general, I'd say, cut these writers a little slack.
You, also, are an excellent writer and I hope nobody accuses YOU of racism because I know from your writing that you are most certainly not that. You posit good questions here. I personally have no issue with the challenges made against Ukrainian authorities regarding the free movement out of the country of POC. It seems like a legitimate issue.
Challenging Ukrainian authorities on this issue doesn't challenge the need to favor Ukraine in the fight against Russia. It just helps keeps things honest.