How would you change the sentence? There no reason why we shouldn't fix that issue right now.

Counterexamples to a definition (this example is under your definition but is clearly not what we mean by confounder) are easier than a definition. A lot of analytic philosophy is about this. Defining "intuitive terms" is often not as simple as it seems. See, e.g.:

http://arxiv.org/abs/1304.0564

If you think you can make a "sensible" edit based on this paper, I will be grateful if you did so!

re: the rest of your post, words mean things. B is a technical term. I think if you redefine B as internal jargon for LW you will be incomprehensible to stats/ML people, and you don't want this. Communication across fields is hard enough as it is ("academic coordination problem"), let's not make it harder by not using standard terminology.

Maybe tabooing Bayesianism as word on LW would be the right choice. Maybe the word produces more problems than it solves.

I am 100% behind this idea (and in general taboo technical terms unless you really know a lot about it).