Contacting Sinclair's advertisers is a great idea, but make sure you're polite and explain clearly why this is a serious issue. And, yes, call stations and ask to talk to the ad sales manager whose livelihood directly depends on this and let them know what you've done.
This statement from Reed Hunt gets at why this is a serious issue, and not just a partisan turf battle.
You can find a list of local advertisers here. Pick an affiliate that's near you.
Apparently, peoples' efforts are paying off.
