They actually don't even bother to sell first party display port adapters for HDMI: you have to get a third party adapter.
However, I do disagree on the quality of third party adapters; there are many fine ones out there, and the cheap mini-dispay to HDMI I bought last time I was in the US works picture perfect. I think it was PNY but not at home so don't remember.
Not to say all are good, but there are quite a few good adapters.