Abstain From the Appearance of Evil is a myth because that is not a translation of the Greek New Testament or of the Vulgate. Both of those agree with the following:

1 Thessalonians 5:19. You must habitually not ever quench the Spirit, 20. you must continually not ever despise prophecy, 21. but you must constantly prove all things; you must incessantly hold fast the good, 22. you must faithfully keep yourselves away from every form of evil.