ATF Wanted to Make Example of Davidians
The ATF wants to disarm American citizens. The ATF particularly dislikes Americans having access to weapons more powerful than hunting rifles, or large collections of weapons. Even worse to the ATF is when Americans with unorthodox religious or political views have large collections of powerful weapons.
The problem, from the ATF's point of view, is that such a situation is perfectly legal. The First Amendment to the U.S. Constitution protects unorthodox religious and political views, and federal law imposes no limits on the number of weapons that an individual can own.
The solution, from the ATF's point of view, is to use minor infractions of the extensive federal firearms laws to justify draconian response.
In the case of the Branch Davidians, the ATF suspected legal, semiautomatic rifles had been converted into unregistered, automatic rifles.
Legitimate Concerns, Illegitimate Response
The ATF had enough information to warrant legitimate concern about illegal activities at Mt. Carmel. The most serious allegations were about sexual abuse of 11 and 12 year old girls.
The ATF was still wrong in conducting a military attack of the Davidians' residence.
Sexual abuse is not in the realm of the ATF, rather it is the realm of state law. The information should have been passed to the proper authorities for further investigation.
Allegations are just that. In the U.S., people accused of a crime are considered innocent until proven guilty. Many of the allegations came from dubious sources, such as "cult busters" intent on destroying the Davidians' religion.
Investigating allegations does not justify a military assault.
Other than the above charges, the allegations used to secure a search warrant involved technical violations of gun control laws, and deprecating innuendo about unorthodox (but peaceful) beliefs and habits.
ATF Had Personal Grudge Against Koresh
The affidavit used by the ATF to gain a search warrant made note of the fact that David Koresh opposed gun control, believed U.S. gun control laws were wrong, and possessed a Gun Owners' Association video portraying the ATF as violating gun owners' rights by threats and lies.