If it is, then you might as well stop being a Christian now, as the religion, however generic you want to make it, would be logically false. If the Catholic Church is man-made, then Jesus, whom we suppose to be omniscient, would have knowingly allowed Himself to be massively quoted out-of-context in His discussion of the Church (whatever it is), and, further, knowingly allowed this bastardized church to go on unchecked and uncorrected for 1500 years before any correction was made. This is an absurd denial of Divine Providence. If that was the best He could do, then we ALL labor in vain, indeed!
Yet, there is an alternative viewpoint here that rectifies the situation quite nicely...
The church established by Jesus continued to exist even after the apostate Catholic church came into existence. By you logic every church that has come into existence that was not "His church" would have been stamped out via "divine providence." God gives man a choice. Either obey the teachings of the Bible or men such as the Pope, Mohammed, or Joseph Smith.