Mathematically not wrong, but most definitely misleading/unethical. I don't think this was done unintentionally either, because the graph would still be perfectly readable without this change (as opposed to "a few points variation" where such zoom would be required)
It's perfectly fine to display data this way, but they should make it clearer that the start isn't 0 by using wiggly lines or by labelling the origin.
It's perfectly fine to display data this way, but they should make it clearer that the start isn't 0 by using wiggly lines or by labelling the origin.