The number of people who are politically disengaged is staggering. What better to motivate those people than to prompt some anger over an issue and hope they care about it enough to stay angry and vote. Also important to note this stuff is never done alone, there’s other outreach happening at the same time. It’s a numbers game, and those few disengaged folks you got fired up with a stupid ad could make or break you.

That said, I think most attack ads are damaging to political discourse by nature of demanding a concise, pithy message. Never going to get genuine criticism out of that.