Let us begin with a caveat. There are no bad management styles. There are just irrelevant, ineffective, improper or wrong management styles. Every style of management has its pros and cons. If practiced in the right context and if the results are attained, then any style of management is effective and thus good. If the results are elusive, then they would be categorized as bad management styles.
The purpose of management styles is not to develop a certain practice just because one wants to. The objective of management is to achieve the goals preset, whether at an organizational level or for an individual. Many people consider dictatorial or authoritative style to be one of the bad management styles. That is not a rational assessment. Authoritative styles can work wonders in certain situations. And in those situations, no other management style would be of any impact. Sure, there may be some grievances among the workforce but then the results are achieved. Not every manager or company for that matter is worried about the means or methods, approach or practice but that the results are achieved.
Bad management styles are those that are irrelevant or not in the right context. For instance, if the workforce is highly skilled, motivated and can get the job done, then there is little sense in having a dictatorial management style. The workforce would not enjoy being bossed around, their skills will not be put to optimum use if all the powers rest in one individual and the teams are just asked to follow commands and in the process the talented people may suffer burnouts and may quit. Types of leadership that fail to derive the best from the workforce or in a given situation would qualify as bad management styles.
In a similar way, if a workforce is lazy, unhappy, uninspired and do not have any significant skill but can do the job, then one has to be authoritative. A leader in such scenarios will have to handhold the workforce and get the work done. Having democratic or participative, consultative or even laissez faire management styles will not work in such scenarios.
As you may realize by now, it eventually boils down to the workforce, the type of work, the nature of business, modus operandi and the scope. All these factors will determine what the good and the bad management styles are.