The linked source is directly from Adobe and directly contradicts the claim that "you need 13.1 to launch in 64-bit."
The source says:
> Photoshop CS6 and CC only install a 64-bit version on Mac OS.
Further, it says:
> Photoshop CS5 installs a version that can launch in either 32 bit or 64 bit when you install on a 64-bit version of Mac OS (Mac OS X 10.5 or later).
If CS5 install can launch in 64-bit, it wouldn't make sense for CS6 to be 32-bit only from the first version.
Even further, I know from personal experience that your claim is highly unlikely. This is a screenshot of Photoshop CS5 (12.0.4) running in 64-bit on my machine (High Sierra). Noticed it says "12.0.4 x64."
I am not sure of the source of your information, but it's simply incorrect.
Edit: This is another article directly from Adobe.
It says:
> On Windows, both Adobe Photoshop CS6 and Adobe Photoshop CS6 Extended have the option to run natively in either 32-bit or 64-bit editions. On Macintosh, only a 64-bit edition is available.
I don’t know what to tell you. Every time I launch CS6 on my Mac it tells me that it won’t run on Catalina.
I have no reason to believe that’s not true.
I think it’s quite possible that when Adobe says “64-bit” they’re not saying exactly the same thing that Apple means. I’m no expert with macho binaries and MacOS library linking.
You need 13.1 to launch in 64-bit, which is only available to CC subscription holders.
Edit: it seems that at one time it was possible for non-CC license holders to upgrade to 13.1 but it doesn't work anymore.