A JW dismisses their dark history and ever-changing doctrines under the fallacy of "new light". You see, a JW firmly believes that "god's people" cannot handle the truth, so as "make weight", god either directly tells the WT to teach error, or allows it, until god gets around to telling the truth. So, even when their former doctrines have been tossed into the trash bin as so much hooey, and current "truths" are re-worked to the point of being unrecognizable, a JW unquestioningly accepts whatever WT currently serves up as "Biblical truth", despite the fact it has a very short shelf life.
.
Jesus is said to have chosen the Watchtower Society as his only means of salvation because it was the only organisation providing food at the proper time, and so justly appointed over all Jesus belongings.
"The serving of food, the right sort of food, at the proper time was the issue. It had to be according to this that a decision must be rendered by the returned master... On inspecting the remnant of his anointed disciples in the year 1919 C.E., the reigning King Jesus Christ did find the appointed slave faithful and discreet in the feeding of his domestics. Accordingly, he appointed this slave class over all his belongings." Gods Kingdom of a Thousand Years Has Approached pp.350,355
Is this really what Jesus found in 1919 when he inspected the Watchtower Society? No, he found the following teachings being promoted:
The "Last Days" started in 17993 and the 1800s were the worst time period of all history
That Jesus presence commenced in 1874
That Jesus had begun ruling in 1878
Armageddon had occurred in 1914
That the end was going to come in 1925
That blood was acceptable as food for Christians
That Jesus should be prayed to and worshipped, as well as Jehovah
That the Great Crowd were a heavenly class
That birthdays and Christmas were acceptable celebrations
The cross was on the cover of the Watchtower
Teachings adapted from Freemasons, such as that pyramids and astrology supported 1914
Strong Zionist support for a new nation of Israel in fulfillment of Bible prophecy
That the Faithful and Discreet Slave was not the anointed, but rather Pastor Russell
Furthermore, the most noteworthy doctrine introduced in 1918 - that the earthly resurrection would start in 1925 - was a false and embarrassing failure.
Are these teachings the "right sort of food at the proper time"? By current Watchtower truth the food the Watchtower Society was providing in 1919 was filled with inaccurate prophecy, spiritism, paganism, polytheism, idolatry and political activism. Certainly anyone belonging to such a religion could not be considered one of the anointed. It brings into question if Russell, who had died in 1916, could be in heaven. Did Jesus go about immediately cleansing his organisation in 1919? No! The reality is that virtually no teachings or Babylonish practices were changed between 1914 and 1919. All of the above teachings were still being promoted in 1925.
http://www.jwfacts.com/watchtower/15-minute-guide-to-truth.php