Artboards in 2018 can no longer be rapidly deleted
In past versions of Illustrator, I was able to click on an artboard and continuously delete artboards until I had to ones that I want. Now when I select an artboard and delete it, the selection is deselected. I now have to continuously highight and delete, highlight and delete until I have removed all the artboards I need.
Jordan Hunnicutt commented
So it's a feature, not a bug. I see.
In Illustrator 2018 you can select multiple artboards, use shift click to select multiple artboards or use shift + drag to select multiple artboards and then press delete key.