Flagging content should be a privilege that comes at a certain level of trust, and the privilege should be revoked by moderators for people that use flags to further an agenda.
Trust in forum users can be measured by various metrics - The Discourse forum software is a good example of how to do this: https://blog.discourse.org/2018/06/understanding-discourse-t...
How do you know that people use flags to further an agenda? I for one both downvote and flag pretty often, but it's largely because I don't like the tone of the discourse, not because of some overarching ploy.
Since it's such a powerful action, it would be nice if flaggers had to at least justify the flag. Is it breaking a site rule? Is it spam? Is it not the original source? Does it actually violate the rules, or are you just using "Flag" as a mega-downvote for articles you don't personally like?
People do get their flagging powers revoked for misuse. There was a time when I went on an overly aggressive flagging spree and my flags no longer had any effect. Months later I sent an email to hn@ycombinator.com to pledge more judicious use of flagging and to request the restoration of that power. I got it back then.