You have a partial point, and I may have been sloppy with my words. But on the whole, you do not, and while I might willingly fool myself about a great many things, this is not one of them. I'm well aware that the license agreement claims to forbid running it on non Apple hardware.
However, no -- the software WAS "legally purchased" AND "not pirated".
I purchased, from Apple.com, a mac-mini, then in the apple app store paid for a stand-alone install of macos. I believe it was $20.
"legally purchased" -- I paid for it through the legitimate channel (as opposed to, say, buying it from anyone other than Apple Inc. like ebay)
"not pirated" -- Piracy (in this, that is, not the captain hook kind) context means taking advantage of the fact that digital assets can be perfectly duplicated to escape paying for it. I paid for it. I didn't duplicate it.
As to the issue of the Apple's "license agreement". On this we may simply view the world differently. It is my viewpoint that once a product is sold the original owner no longer is entitled to a reasonable expectation of control over its use. I can buy a screwdriver labeled "Only for use with Lowe's(tm) screws", and use it on whatever brand screws I want, because it's my screwdriver, and the notion that Lowe's gets to exert control over how I use a tool after I've legally bought it is
I am aware that currently some interpretations of US law are not congruous with this. I frankly don't care. You have the right to believe whatever you want, but to me law does not define truth. Interpretations of law frequently codify things that are not.
Regardless of bills passed or the outcome of court cases corporations are not (yet!) sentient entities, in 1897 Indiana the ratio of the circumference of a circle to its diameter was not exactly 3.2 -- it was pi, just like today, and all of my family members are equally human beings as anyone else despite much older laws asserting that some of them were 3/5th.
"fooling yourself" is a waste of effort. I'm well aware -- I have no romantic delusions about, for instance my copy of IDA Pro or MATLAB for example. It's a tool I greatly benefit from, that I cannot even come close to affording, so I stole it. Sure, it's almost certainly the case that in the coming years I'll again be in a position to legally purchase several licenses for work use, but that doesn't change the fact that I still pirated them.
But no, I legally purchased my copy of MacOS, it is not pirated, and I do not believe in the waste of time that is fooling ones self.