I am a PhD student. At the beginning of my study, my supervisor told me that they are able to help me with my topic. However, later I found that they cannot even understand what is my topic. They wasting my time for more about one and a half year without any comments or help with my topic. Then, I worked entirely alone with my topic. I have done the first chapter of my study, they asked me to be co-authors with me for nothing but just because they are my supervisors. I refused this. Then, they asked me to add them in the acknowledgment as they are the supervisors of this project. They asked me to write this in every single paper of my Ph.D. papers. They did not help me with anything, they even cannot understand the difference between my objectives. My question, Must I acknowledge them in my papers?
Acknowledging your supervisor means many things, ranging from thanking their funding and fundamental supervision to suggesting that your phD relationship is ok, although this is not necessarily the case.
Non-helpful supervisors are not only those who ignore their duties but also those who do not give the input but keep pushing you back. So, my suggestion is to change your supervisor. Move on to work with more professional people. Doing research alone is hard enough. You don't want any other barriers in your way as your journey will become harder and harder.
Giving a mere acknowledgement to supervisors is a pretty low bar, and it would be a pretty extreme reaction to deny this. Even if they did not succeed in assisting you with this paper, presumably they must have made some attempt to assist you in their supervisory role, and they have taken time out of their own schedule to try to assist you as a student. That in itself warrants an acknowledgement and thanks, even if you are of the view that they did not contribute anything of value. It is usual to add someone as a co-author only when they have made a substantial contribution to a paper, but the bar for an acknowledgement is much lower.
I note from your further comments that you are of the view that your academic supervisors do not understand your topic, and the Dean of the Faculty is "with their side". I also note your comment that they have asked you to withdraw from the university, or at least take a long vacation. Under such circumstances, you should try to engage in some self-reflection and see if you are acting reasonably, or if you might be contributing to the problem. Refusing any acknowledgement of assistance (or at least attempted assistance) by a supervisor suggests that you are not acting in a manner conducive to good relations with your supervisory panel.
It is not entirely impossible that a supervisor could be incompetent to assist a student, or that a Dean could incorrectly side with the supervisor in this case. However, it would be very unusual if multiple professional scholars do not understand the topic of a student they are supervising, and are not able to provide a student with any assistance. Application of Occam's Razor would lead an outside observer to conclude that the more likely explanation is that it is the student might not properly appreciate the efforts made by their supervisors. The refusal even to acknowledge and thank them in a paper contributes to this perception.
However, later I found that they cannot even understand what is my topic.
Then, they asked me to add them in the acknowledgment as they are the supervisors of this project.
simply don't add up. If they are supervisors of some project, chances are they have written the proposal of the project, and defined aims/goals/methods etc.
Moreover, because you are involved in a project supervised by your advisor(s), no matter what you do, they must take some credit. Without them, the project wouldn't exist. Without the project, that particular work wouldn't exist.
A similar reasoning is, when you publish a paper, you write the name of your university even though the university did literally nothing.
By the tone of your question and your tendency to self-righteousness, I think you should be more worried about your future in that project. If your tone to your supervisors is as rude as it is in this post, you probably will have a hard time in near future.
Whether you must add them to the acknowledgements is, I guess, down to your institution.
From a practical and pragmatic perspective, you should add them to the acknowledgements. It doesn't cost you anything, except perhaps some pride, and it avoids worsening relations between you. If you're going to have a fight with them, save it for something that matters :-)
This is likely to be Country and / or Institution dependant, but have you considered speaking to the Dean or the next level above them?
Is there some type pf PhD committee that could help?
Do consider that they may become vindictive if you do not include them and could cause harm or slow down your continuing progress...