The WTBTS/ Org dictates to its subservient followers what constitutes a Bible truth/principle and what does not.
Example: it-1 p. 319 Birthday - ".....there is no indication in the Scriptures that faithful worshipers of Jehovah ever indulged in the pagan practice of annually celebrating birthdays. The Bible makes direct reference to only two birthday celebrations, those of Pharaoh of Egypt and Herod Antipas."
The Org's cast-iron "scriptural reasoning" - that any act/practice/celebration which the Bible records as only false worshipper having done, must be pagan and sinful - should be applied in every case.
2 Kings 9:30 says, "When Jehu came to Jezreel, Jezebel heard of it. So she painted her eyes with black paint and adorned her head and looked down through the window."
Therefore, the WTBTS should warn every baptized sister that applying mascara will now be a disfellowshipping offence!