Its possible they have some sort of relationship with the Dancing With The Stars show that requires them to have someone from the show.
A lot of times it is only 3-4 questions before they do a dance and are off the show.
I don't particularly disagree about him not being a good idea as a guest. You never know how she will handle it. It might not be as much a puff piece as you think.
In any case, you should keep in mind that the Ellen and her staff are unlikely to see stuff posted here.
In the past there has been some monitoring, but with the drop in activity here, I wouldn't be surprised if they mostly stopped monitoring us.