Title IX is the law that requires equal opportunities for women to participate in athletics. In the Caster Semenya case, Cornell law professor Dorian Lambelet Coleman argued on behalf of the IAAF that allowing biological male athletes to compete against women violates the public interest served by Title IX. Whether transgender athletes should be allowed to compete against women is considered a matter of public concern.
You also misspoke when you said that the coach said Telfer couldn’t cut it as a man, he said “male athlete.”
This statement, while perhaps capable of being interpreted as insulting, is still clearly related to the fairness of allowing transgender athletes to compete against women. So the correct legal answer is yes, if terminated for making these statements, the coach would indeed “have a case”.
I do not mean to tell you which posts to respond to. If by your reasoning condemning posts which we all agree are bigoted, factually incorrect, logically inconsistent and legally invalid makes less sense than attacking only mine, forcing me to repeatedly prove that my posts are none of the above, then knock yourself out. I would still be honored to fight for your right to disagree with me all you want, because unlike coach Emerson, I understand that a more fundamental freedom than the right of transgender athletes to compete against women is the right of all citizens to robustly debate matters of public concern without fear of losing one’s livelihood (or of being put in jail, for that matter).