Suggesting competitors as a "spelling alternative" is a bit off though init really.
They p!ss me off with the "searches related to" also, which tend to list direct competitors. I find that Bing on the other hand lists truly related and useful searches.
Wildbest is right. This sort of behavior is like a protection racket when it constitutes an incentive to engage with Adwords, or particular keywords you would not have otherwise bothered with.