I find I disagree with this, sorry. Making Wally black is a big deal and does seem like forced diversity and it is kind of disrespectful and offensive.

People wanted Wally West, the character that an entire generation knows as The Flash. He had years of development and became a much loved character and he was thrown away in order to reintroduce a character who people had largely moved on from. They wanted to bring back Barry and that's fine but they did at the expense of Wally and that felt like a slap in the face to his fans and was disrespectful to them, the character and everyone who had built him up into what he was.

But okay, they're going to bring Wally back but younger. That's okay, we can see him grow back up into the character we know and love. Except this isn't Wally West. It's essentially a new character with the same name. Why not just give him a different name and say he's a new character? Call him Michael Smith and there would never be an issue. But Wally is tied to the legacy and what better way to force a new character onto people than to just say he's an existing character? This again shows a serious lack of respect for the audience and for the new character. They don't think people will accept a black Flash character? Or do they just not think this character is anything special and it's easier to piggy back him off an existing legacy rather than try to give people reasons to accept him? Or maybe they just did it too shut people up about Wally. So yeah, this isn't the Wally people know or the one they wanted and him being black is a small part of that.

But let's say he's actually exactly like the Wally we knew. What was the point of making him black? Ethnicity is not a switch you can flip. So it would have been forced diversity like people suggested. They need more non-white characters so just make a white character black? Shouldn't people be offended by that? Ethnicity or skin color doesn't affect your personality but it can affect how you might fit in the world. Some people will treat you differently, your experiences may be different, things like that. That all effects your mental and emotional growth and you'll develop a different world view than if you were a different ethnicity. That's not to say that's bad or those experiences will have a negative effect or be negative but it's a fact. You mentioned it yourself with the stuff about white privilege. So saying someone is the same character but a different ethnicity seems a flawed premise and a little offensive.

And making the argument that changing a black character to white is an issue is perfectly valid. If you can do it one way you can do it the other. You can't say it's not a big deal when it goes one way but it is when it goes the other. That's an unfair double standard. I'm not going to argue things like privilege, I know all that. I understand why it's offensive to make a black character white, I'm just saying it's no better the other way around, though perhaps for different reasons.

Anyway there a lot of reasons why we should be offended about the Wally change and him being black is one of them. It's not racist to think that way. This could have been a chance for them to bring in some diversity and introduce a great new character but a lack of respect for fans and the character turned it into a mess. They blew it, plain and simple.