> As someone else pointed everyone is already on DST for approximately 65% of the year. This just removes the remaining 35%. Picking standard time would have been a much bigger change.

This 65% started during the Dubya presidency (source: I was there updating tzdata on systems), and previous to that it was a 50/50 split.

So 65/35 or 50/50 is arbitrary.

But the reasoning for that was a preference for DST.

Obviously all this is arbitrary including standard time.