What you're describing is purely hypothetical, and dependent on the idea that NiP can just make other people agree with them because they're bigger than Anonymo, which is a completely arbitrary metric. People are already skeptical of anything NiP says because they have a shady history regarding how previous management dealt with player payment. It's HIGHLY unlikely that NiP could convince other orgs to boycott Flashpoint unless they already believed themselves that Flashpoint was an incompetent org.
The legal argument is extra stupid, because again, it hinges on the public image of Flashpoint not already being in the dumps. Regardless of how you think the verdict should go, they fucked up the situation and their public image is currently shit. The idea that NiP going to court over this (which is already an extremely flimsy and unlikely scenario) again relies on people already believing Flashpoint is shit, because otherwise it just makes NiP look worse.
The investor argument is even worse. Why the hell would Flashpoint investors (many of whom are the partner teams btw) listen to a single team? They're not even the biggest team in the league, and it's not even close. If teams could just go to investors and tank entire tournament organizers based on admin decisions they don't like, why the hell has no one done that before? Oh yeah, because it's not realistic, and not how anything works in the real world.
If anything tanks flashpoint it'll be their own fucking incompetence.