Should I list people who are in competition with me as reviewers to exclude for "conflict of interest"? I am submitting a a paper to a top conference and I need to determine the reviewers with conflicts of interests. 

There is a big competition in having papers accepted at this conference, among people working in this area. Also, it is very likely that my paper goes to people who are in the same area for judgement. Particularly, some of these people are not very honest and they blindly reject other people's works, in order to publish their own papers. To myself, it has been proven the dishonesty of them.

Is it OK to put these people in my list of reviewers to exclude because of conflicts of interests? There are other researchers who can judge the quality of my paper honestly, because I am not putting everybody on that list. But is it right to do so?
In my experience, when a conference asks authors to identify reviewers that are conflicted, they want you to identify reviewers who fall into certain categories of people who should not review your work because they have a relationship with you personally that could bias their review. For example: your advisor, your colleagues, your current collaborators, your family members, etc. They are not asking you to list reviewers who you consider to be your competition.

For example, the instructions for POPL 2017 say:


  As an author, you should list PC and ERC members (and any others, since others may be asked for outside reviewers) which you believe have a conflict with you. While particular criteria for making this determination may vary, please apply the following guidelines, identifying a potential reviewer Bob as conflicted if
  
  
  Bob was your co-author or collaborator at some point within the last 2 years
  Bob is an advisor or advisee of yours
  Bob is a family member
  Bob has a non-trivial financial stake in your work (e.g., invested in your startup company)
  
  
  Also please identify institutions with which you are affiliated; all employees or affiliates of these institutions will also be considered conflicted.
  
  If a possible reviewer does not meet the above criteria, please do not identify him/her as conflicted. Doing so could be viewed as an attempt to prevent a qualified, but possibly skeptical reviewer from reviewing your paper. If you nevertheless believe that a reviewer who does not meet the above criteria is conflicted, you may identify the person and send a note to the PC Chair.