There's so much wrong with the fact that the network did this that it's hard to know where to start. And I should point out that it's not just ABC. All the networks do this to one extent or another on their over-the-air broadcasts. Some actually interrupt programs, while others put their logos or weather maps or whatever over a good chunk of the picture. Both approaches are terrible.
Let's begin with the fact that this is just a primary election. There's going to be non-stop news coverage of this election for months yet. There is no good reason for inserting "breaking news" on something that has no relevance for months to come, and will be covered to death on the next scheduled news broadcast anyhow. Worse, that primary election wasn't one that's even in my timezone. I could maybe see interrupting broadcasts in the New York or even New England area for updates, although even that is far from useful in this day and age. But the rest of the country? That's just stupid.
Network program people, let me introduce you to this new thing we have. It's called the Internet. You can get news updates any time you want, practically instantaneously. I personally have no less than 5 different devices in my living room which could get presidential primary election results within seconds. The same applies to weather alerts, school closings, news about the queen's birthday, etc, etc. I do not need my TV to be a 6th option.
Even if you feel you must cater to the very small set of people who both care about your update and have no Internet access, there's another new thing that you program people may not have heard of: bottom of the screen scrollbars. You can put your useless information updates on the bottom of the screen, while the picture is scaled slightly smaller on the remainder of the screen. The show continues uninterrupted and with no blocking of the picture. It's amazing!
Then there's the fact that I was watching this well after the original air time. I realize that broadcasters don't want to cater to people who record their shows and watch them later (while skipping the ads), but it's a fact of life that people do this. Lots and lots of people. And you know what those people do when you do stupid stuff that messes up their viewing experience? You might think they'd get it from the network web site, but those are terrible as well - the shows generally aren't available for days after the original airing, they have even more annoying ads than the ones on air, and the quality is often poor. No, people will go to the Internet and watch your content via pirate sites, which have no commercials and HD quality and episodes are available mere hours after air time (if not earlier). You want to keep people from stealing your content? Stop making it a terrible experience to get the stuff legitimately.
Feel free to join us in the 21st century any time, broadcast TV networks. Meanwhile, we'll be on the Internet.