[mwrouse]

While this is an interesting article on history, this isn't an actual criticism, is it? I've never heard this criticism.

I really don't think saying "a = 1; a = a + 1;" is the equivalent of saying "1 = 2" because "a" is a variable.

[jholman]

It's a very common criticism.

And as a teacher of programming to adult students, this causes a small amount of wasted time with the overwhelming majority of students, because they know what "=" means, even the non-mathematical ones. Usually not a huge obstacle, but a perceptible one.

And once they learn that it's a mutating assignment, some (small) fraction of students continue to forget, for an infuriatingly long time, which direction the mutation goes.