It's simple: EA is a public company. They have obligations to their shareholders, and keeping them happy requires them to do things that keeps them happy, even if they don't necessarily work the way the shareholders think they do.
Always on DRM doesn't work, and hurts legitimate consumers, but it gives shareholders the impression that the company is effectively protecting their software from piracy.
Notice how Valve and Zenimax, companies generally beloved by gamers, are both Private. Blizzard was also Private before merging with Activision.