I can see how those people who are, for example, “atheistic, but not antitheistic” might want to distance themselves from the (alliterative) antitheistic atheist authors, but can’t they pick a different word?

Therein lies the problem – people with 99.9% overlapping views deciding that because they differ on what is almost always a relatively minor thing, they need to “distance themselves”. I’d argue (if I had the inclination, which I don’t) that many of the terms you used are just different facets on the same thing. But then I don’t feel the need to describe myself as a “freethinking skeptic secular atheist humanist slightly-antitheist apatheist”, it’s just not a subject that interests me, other than from a historic perspective :-)