Why are the built-in opamp models upside-down?

[ML9104]

Thanks.
Based on this thread, I created a more general-purpose FAQ on this subject:

KiCad 7 & 8 Alternate Schematic Symbols: How to Create Them

This FAQ is about regular and alternate schematic symbols in KiCAD, a feature that can be extremely useful. It is only possible when using Personal Libraries, the reasons are explained in this FAQ: Read it first. Is there an alternate symbol functionality in KiCAD? Yes, it’s there, but it has a non-obvious name: De Morgan. Originally made for logic gate transformations, it’s universal enough to be used in a general way, which is nice. The official documentation does not really address this…