ATF is not something that I would make use of in general. It's effects on decals is not nice. It might be useful as a cleaning solvent.
OLD oil is bad, on that we can agree. However, unless your intent is to clean and long term store without use, I see no issues with SM Oil. It is the dried oil and oil/gunk in the nooks and crannies which is the issue. Dried Oil (Varnish) is sticky hence the "stuck" machines.
I cannot see how PTFE(Teflon) "residue" will be an issue in times to come. Unlike Varnish the Teflon, even when dry, is a lubricant. Alcohol works great for removing the PTFE FYI.
I do have an old mostly worthless stuck machine that I will try the ATF on to see what I can learn from that.
Thanks for the alternate view