Huh, I had not heard that. In my experience it's pretty evenly split -- at least, in my circle of friends and family there's eight black cats, four of each. (Most short-haired, one long-haired black cat that's female.)
Cat coat color is an X linked gene, so there's no representation of it on the Y chromosome.
Let's denote this as Xo and Xb for the genes. An orange female cat is XoXo, a tortoise shell / calico cat is XoXb and a black female cat is XbXb.
Male cats are either XbY or XoY - there are no tortoise shell male cats (there are cats with Klinefelter's syndrome that can be XbXoY but only mentioning this for a full coverage of the topic - and for a real example of this https://disneylandcats.com/cat-profile-francisco/ and it confuses things since XbXbY and XoXoY cats would be difficult to identify without a genetic test).
The thing with all of this is that the genetics for XoXo or XbXb and XoY or XbY are exactly the same percentages.
Doing the Punnett squares for cat coats and all the possible pairings and you get simplified
Genotype Count Percent of XX or XY
XoXo 3 25%
XoXb 6 50%
XbXb 3 25%
XoY 6 50%
XbY 6 50%
It ends up with 2/3 of the orange cats being male and 2/3 of the black cats being male. This doesn't quite match real world situations since you could have a colony that is dominated by orange cats (or black cats ... or neither).
Also noting that you can occassionally get a "tortiose shell" esque male cat via a pretty rare process known as chimerism. i.e. two or more different embryos merge in the womb resulting in different parts of the body being formed from different embryos (meaning different DNA depending what part of the body you sample from). And of course for this to result in a cat you can see, they have to get lucky enough that the combination of embryos still produces a viable fetus.
Not to take anything away from the info you've provided since it is all interesting. But it seems francisco's gender is pretty debated. There are a few that talk about them being a female with certainty, but without any reasoning I also take their info with a grain of salt.
https://youtu.be/wPVBGE6uUS4