This is a good way to look at it, I think.

But their own experiences seem to me to be pretty one-sided. I haven't read their books, but on Medium when I read Tim Wise I started to ask myself: does he ever wonder whether some bad thing was caused by "whiteness" but then realize, no, it isn't? It was something else?

This basically never happens. It's always whiteness. And always bad. All bad things, all the time. If something is not as it seems, it's always that whiteness is secretly lurking behind something bad, or something is secretly bad that initially seems innocuous. It's never the other way around (that I've seen).

This says to me that whether or not he has a highly one-sided experience, he at least has a very one-sided presentation.

You can still learn from a one-sided presentation. But when so little evidence of discerning thought is in evidence (rather, only confirmation and elaboration of a particular view), I don't think it should inspire much trust. Rather, one can use it for inspiration to ask: hey, what about this thing Wise is talking about? Is this actually bad? How bad? How do we know (both consequence and intent)? Are we getting an accurate picture or a distorted picture? If distorted, what else do we need to learn or consider to regain an accurate picture?

For example, systemic racism is real and well-documented, and we should combat it. However, most people who talk about it like to cite a paper that's 20 years out of date about hiring disparities in the U.S. revealed by racially suggestive names on (fake) resumes, which shows a 50% penalty for people with black-sounding names. Much bigger and more recent surveys exist, which confirm that, yes, there is still this sort of structural racism, but now it's only about a 10% penalty (and furthermore, most of the average penalty is the result of a small number of employers being quite racist w.r.t. inviting people for job interviews, not everyone being mildly racist all the time). Almost nobody ever cites the huge recent study. And there's another paper that contrasts names that sound African with those that sound black American...and most of the bias is against the perception of black American not African identity, which indicates that it's likely a stronger reaction to a perception of culture than a perception of race. Almost nobody cites that paper either.

If we don't understand the situation as it actually is, what hope do we have of rectifying it?