I don't disagree, but I do think it's important to note that any two high school experiences can differ drastically. For someone who is barely making it through high school academically, their high school diploma may represent a basic level of math and other subjects. For someone else who is in advanced or AP classes, their high school diploma is going to be substantially more advanced than what the GED is. The GED is a fairly basic measurement. I don't think I would consider it high school equivalent, although when there is a requirement for a high school diploma, it is absolutely true that a GED will nearly always suffice, so from that perspective they are equivalent.

Edit: also worth noting, is that I know of people who have graduated high school who probably could not pass a GED. It is definitely possible in the right school to coast your way to graduation, even if you would not meet the normal expectations. So in those cases, a GED would be superior to a diploma. All of this I think indicates that high school diploma is becoming somewhat meaningless