Is there anything unlawful about offering to cover legal fees for everyone wanting to pursue good-faith legal recourse (including arbitration) against a particular company?

For example, suppose I'm a mega-billionaire who simply finds Facebook's conduct abhorrent. So I offer to pay for the Binding Arbitration fees of every Facebook user who has a plausible claim against Facebook.

And would the legality of that change if I was majority stakeholder in one of Facebook's competitors?