There are two different kinds of estrogen receptors. Up to a certain amount of soy it affects mainly the receptors not associated with harmful effects. So a certain amount of soy per day is safe & healthy. But beyond that it can be problematic.

https://nutritionfacts.org/video/how-much-soy-is-too-much/

It should be noted that feeding babies milk from cows is an "experiment" too and there's a lot of evidence it's not good for them.