It was a very limited study (it involved 8 people), with very limited conclusions that don't justify this:
Joanna Harper herself doesn't come close to this conclusion: She effectively says that in some sports it won't have an effect, in others it will. This isn't controversial - it's quite clearly self evident that this won't track across the board. Joanna herself gives the example of how transition therapies won't make you shorter - and this might aid you if you're transitioning as a basketball player, but cause you to lose out if you're transitioning as a gymnast. Her study was very small - and unfortunately it's a bit of a chicken-and-egg situation, because you simply don't have many trans athletes whom you can study because it's so relatively hostile. This makes it very difficult to find study groups. But Harper's is a limited, small study whose conclusion is specifically about running, and more broadly that some effects are nullified, others aren't and thus the comparative advantage will vary from sport to sport. This is Harper's *own* conclusion.
As such, the idea that "anyone concern posting about genetic advantages by transgender women in competitive sports or claiming transgender women have genetic advantages will be treated as transphobia and/or spreading misinformation" is ludicrous.