Why don't catholic & orthodox 'churches' not understand that practice of "intercession of saints" is idolatry?

What you said about history of christianity and anti-christianity(catholicism) is very much correct,despite the fact that catholicism and orthodoxy is being used by satan to make the spiritual eyes of the people blind.Sadly,from the answers here it's clear that world is even today bound by chains of deceit,chains that satan wound around their eyes,so that they will never open their mind to true history of mankind and universe...unless God renew their spirit for repentance,and acceptance of eternal blood sacrifice of messiah Yashua...but word of God clearly predicts,that in the times of the end,before the coming back of Yashua, God will pour out his spirit on all flesh...that means final protestant church the god's church will encomp all mankind(all people living on the face of the earth after the soon coming WW3 will be members of god's church) although many will continue in their sins secretly and miss the amazing rapturous visitation prepared for them by their creator-the feast of the lamb who was slain aka feast of messiah Yashua aka feast of christ Jesus.