There are very significant legal safeguards against frivolous lawsuits. Any lawyer involved in the filing of such a suit can be sanctioned (big $, and potential discipline - but the latter is rare). And anyone who brings an unwarranted suit in their own right (pro se) also can be sued by the defendant for damages (or if criminal laws are involved, is subject to charges for malicious prosecution). There are also those people who repeatedly bring unwarranted lawsuits who ultimately end up in jail for contempt.
This particular case will not likely get past the summary judgement stage, and will never see a jury. It is a fun public interest story, but hardly an indictment of the US legal system.