My entire life has been a lie

Yup. Same way you should pour oil into your car. It prevents an air bubble from forming in the now vacant area in the back of the container. The bubble then tries to escape by bubbling up through the fluid.
If you've ever seen "Beer Fest" it's the same idea with drinking from a boot of beer.

Also if you tilt the cup and put the tip of the soda/beer bottle against it then pour no foam will build up

NO WAY !! i gotta try this asap

I've been doing this wrong from the moment I've been able to hold a carton in my hands by myself

I saw a video trying to prove this food hack on orange juice. It didn't make much difference apart from there being less orange juice.