Free books are an entirely different beast of course. They don't benefit from sales ranking etc. With free books, yes, you can and probably should get them out wherever you can - and why in the world not?
As for Todd's comments, I wholeheartedly disagree with him, of course. I think getting frazzled doesn't help anyone and just catering to all sorts of outlets just because there is this one person who "always" buys there is - in my opinion - a wasted effort. Every outlet will have some loyal fans, and for good reason, most likely. That does not mean they will go there exclusively and more importantly, this is not necessarily in your best interest.
As the publisher of books I have to do what makes most business sense for me. Of course, making my readers and customers happy is on the top of the list, but there has to be a balance. To sacrifice a major part of my product quality and put my books up on Smashwords so they will find their way onto Diesel's shelves is just not a good option, not to mention the time it takes. From a business standpoint, for me , it simply makes more sense to drive even that one Diesel sale to Amazon or so so that it will be put to best use for maximum effect.
But, of course, not everyone agrees with that, and it is perfectly fine with me.