I'd say changing something for vague aesthetic reasons is far more wasteful than doing so to make things more accessible. Compare the cost of installing a curb cut vs. filling it back in because you think a straight curb looks "stronger."

Whether or not serifs actually make text harder to read, at least there is some plausible justification for the original change. Maybe it was stupid at the time, but it's done.

The justification here is petty and wasteful on its face.

No one said it can't be changed back. No one called anyone weird or Hitler. They just said that "it was wasteful to change it from X to Y, so I'm changing it from Y back to X" isn't a logical argument.