I can understand your frustration at what seemed to have been expressed as zeal and dogma. I too have been in yoga classes and felt like I wasn't being given a chance to find what was true for my body. Given that, consider that you might not need to use your pecs to broaden the back. There are other ways to melt the heart and still keep an openness in the back of the heart that are incredibly powerful and enhance so many other asanas as well as breath capacity. I hope you do try this. It doesn't inherently contradict Anusara or the importance of keeping the shoulderblades firmly and fearlessly on the back.