“Abstraction After Warhol” featured 11 painters, most not using brushes

The abundance of self-anointed anti-establishment shows reminds us that nothing in the art world is sacred

Rudolf Stingel at the Whitney, Raymond Pettibon at David Zwirner, Julie Heffernan at PPOW, Georgina Starr at Tracy Williams, and Ingrid Calame at James Cohan