Why does smoke from a soldering iron ALWAYS go towards your face

Because you are not using a smoke absorber to pull it away. Anyone that does a lot of soldering should have one:

https://www.amazon.com/s?k=soldering+smoke&ref=nb_sb_noss_2

I suspect the actual answer to your question is the updraft around your body due to body heat. Bodies have heat plumes, bacterial plumes, CO2 plumes, DNA plumes, virus plumes, and more.