Earlier quoted context omitted.
"If so I wonder who funded the original lawsuit -- was that not enough -- or was this the idea all along?" The plaintiffs law firms "funded it" by working for free, on a contingency basis: if plaintiffs win, the law firms get paid for their work. They won. Now they seek payment for their work.
But instead of from their client, they seek payment from their victim—the company's shareholders, including market indexers such as retirement funds.
Their client is a group of the company's shareholders.