i've heard some people say that chen style doesn't adhere to the theories of the tai chi, but i don't see how it doesn't.

why did lu-chan/jian-hou/cheng-fu (whoever you think slowed tai chi down) slow down the system and emphasize hardness within softness?

it seems that the chen and zhaobao styles are the only ones that really cling strongly to tai chi theory (fast & slow, hardness within softness & softness within hardness). when an opponent uses hard force, you respond with soft force. when an opponent uses soft force, you have to reply with hard force, right? if that is so, then why do most tai chi styles practice with all/mostly hardness within softness?