I realized this is because it was still using the alpha from the png, but from the color input of the image, plus it it had set the color space to non-color https://i.imgur.com/A9rOTjk.png
So I made the alpha it's own png image with just black and white, and used that for the alpha, which made it import correctly: https://i.imgur.com/H32ZEnO.png
This happens until I go into the settings of the material, and change the "blend mode" from "opaque" to "alpha blend". This setting does not seem to get saved when I export the objs.
So my question is: Is there any way to fix this, or will people have to change that setting manually every time they import one of my objs into cycles?