It only makes sense if you grow up with Fahrenheit. Otherwise Fahrenheit isn't how humans feels since most of us have no concept what these number mean.
If I would just go with 0 - cold 100 - hot I would assume 50 - perfect. But 50 is still chilly. 70-80 feels like it should be getting hot but that's the most comfortable temperature.
A lot of users are also from poorer countries that lack the means to create their own web infrastructure. Using Facebook to run your business account is easier, cheaper, and more reliable than most alternatives there. Phone carriers and ISP often also have "free"-data for certain social media platforms. You get 1GB+1GB for Facebook/IG/YT/Some Game. So you are stuck in this loop where everything reinforces itself to use Facebook.