Yeah, you're absoutely right here, neither the Daddies nor the Zippers were ska bands. They were part of that brief lived big-band/swing revival in the 90's you mentioned.
To get a little pedantic about it, the real defining trait of ska is the "ska rhythm" where the guitar plays on the off-beat, or the upstroke, or "skank". is a pretty good easy to hear example of that guitar rhythm.
But to most people, the thing that was most noticeable about ska at first listen was the horn sections. Especially in the 90's third wave, when rock and rock adjacent bands were not really using horns anymore. So it was really easy to lump in both CPD and SNZ as "ska", as they both came out around the heyday of third wave ska, when the Bosstones, Reel Big Fish, etc. were all blowing up, even though they didn't use ska rhythms at all.
One thing that is kind of funny to me is that Sublime was way more of a ska band than either of them, but since they didn't have a horn section, I never much heard people refer to Sublime as ska.
The other day I was seeing 13.1 million people, now I'm seeing 4-6 million, these are some big gaps.
A ton of people either way, but anyone know why the discrepancies are so big?
I can't even imagine how people are counted for things like this. The one I went to was in a town of about 100k total people so I'm sure it was on the smaller side of things, but if asked how many people were there I'd guess around 2000, but that would still just be a completely wild guess essentially. Is that how they count attendance for these things, wild guesswork?