Because in most all of these churches there are truths. They have pieces of the gospel, but most of the founders of these churches readily admitted that it was not the full gospel, but rather the best they could do.<quoted text>If a holy ghost was verifying truth, why so many different opinions of what god wants,why so many religions, why so many denominations, who so many sects?
Roger Williams even said that until angels and apostles visit the earth, God's church would not be here. Nevertheless, they all are able to feel the Holy Ghost because of the truths that exist. Everyone feels the Holy Ghost differently, therefore it is difficult for some to separate prompting a from the Holy Ghost, from their own thoughts.
There is a difference however between feeling the influence of the Holy Ghost and the gift of the Holy Ghost through the priesthood authority of God.
Jesus prophesied that there would be a falling away from the church hat He established. And in Revelations, John tells us that the Heavens would be rolled up like a scroll and God would not speak to man for a period of time. This period of time, we call an apostasy, because there was no one appointed to receive revelation from God, therefore different interpretations of scripture began to occur. Questions needed to be answered but there was no one to receive revelation to answer the questions definitively.