Provocative title aside, Gilles’s article is ostensibly about the ascertainability requirement. That said, it seems remarkably unconcerned with cases that actually discuss ascertainability. (For example, it tries to tie acertainability doctrinally to either predominance or the notice requirement, ignoring those cases where courts have developed ascertainability from numerosity. The article also doesn’t concern itself with merits-based classes, even though these classes wind up vexing a number of courts at certification.)
What "Class Dismissed" does do effectively is look at the different rhetorical anchors for class actions. She labels pro-certification thinking as "liberal" and concerning itself with "public law," while anti-certification arguments are more "conservative" and stem from a conception of "private law."
So, shorn of the ideological labels, "Class Dismissed" identifies a pair of rhetorical strategies that plaintiffs and defendants use in the certification debate. Plaintiffs will often stress the "public law" function of a class–how it will deter misconduct and get relief to those who need it. Defendants will stress the fact that a class action is not an attorney-general’s parens patriae case; it’s a private lawsuit on a large scale, and that means that the court may not take shortcuts just because the plaintiffs’ attorneys call themselves "private attorneys general." They will also point out that the Rules Enabling Act requires that a class action not enlarge any substantive rights.
What does this mean for defendants? That it’s important to keep what she calls "private law" rhetoric front and center in briefing a class action, most importantly because that rhetoric tends to line up best with the legal doctrine surrounding class actions. There is no question that many people–including judges and juries–can find arguments about deterring or punishing alleged corporate misconduct to be persuasive. If they didn’t, there would be few punitive damages awards. But courts are also wary of overstepping their role as arbiters of actual disputes. As a result, they treat class actions as carefully-circumscribed exceptions from the usual rule of one-on-one litigation, and a defendant can rarely go wrong reminding them of the need to do so.