It's quite Simple.
Although the lawyer doesn't expect to win, this will take very little of his (the lawyer's) time to process up to the "thrown out of court" stage. Likely it will be up to the legal secretary to do all teh paperwork and the lawyer will just sign stuff.
However, in the extreme unlikeliness that this actually runs then the lawyer will quickly turn it into a class action and then reap fuckloads of fee money.
Like I say, unlikely to win but it only takes a few seconds on Google to find a big list of really stupid lawsuits that have been won so you never know........