(-) precedence

[Albert Chan]

This is just a guess, but I think all this unary minus stuff orginated from Microsoft Excel.

I had checked Lotus 123. Regarding unary minus, it got it right (-2^2 = -4)
There was no reason for Excel to veer away from the spreadsheet market leader. (back then)

Excel probably get the precedence wrong, but decided to "fix" its documentation, rather than the code.

Just change the precedence table!
It is a feature ... not a bug!

It is all donwhill from here. Others, knowing the flaw, were forced to follow, to be Excel compatible.
As an example, OpenOffice Calc had the same bug (-2^2 = 4)