But that is not for historical reasons, that is due to the universal mathematical properties of the intervals.

The names of the notes and scales are due to historical reasons, but a major third and a fourth is one semitone apart due to math, not history.

What the article means is: we dont have 12 notes (A B C D E F G H I J K L). Instead, for historical reasons (the choice of CMaj/Amin as a reference due to the notation evolution from heptatonic scales) we have A B C D E F G and we annotate with accidentals but, since those are not evenly spaced, there are some missing "black keys" there.

Also, what devnonymous says, which I agree with too (but that's another story...)