To me, this would be the expected second step, for someone infringing on their trademark. Like if a person steals your car, then you confront them and try to strike a deal to prevent involvement of authorities. If you ignore that, I think it is reasonable to expect them to report you to the police, and you to get charged with theft.
I don't think they expect to actually get 15M from this suit. Honestly, it seems like they wanted to avoid the suit altogether, because of how it looks from a PR POV.
I’m not GP, but I can take a crack: A case against a limited liability corporation for infringing on a trademark is not like murdering someone and burning down their house because no one ends up dead and no houses are burned down, and it is an appealable judgement made by a court based in legal precedent.