As far as I can tell the clearing of the camp happened months before this and was not even initiated by either wal-mart or other company that apparently did some clearing as well.

They also would have needed zero permission to clear the camp if they wanted to. Wal-mart could have, at any time, notified the people in that camp that the were trespassing and then either had them arrested or had them formally evicted depending on how the camp fell within state law residency.

This seems to me more like they just figured that once they left, if the land was cleared they wouldn't come back, and the clearing was only illegal for environmental reasons, not anything related to the camp.

Why would the homeless camp be a smokescreen? What benefit would that be?

I see two options,

A: The trees were removed to deter the homeless from returning by removing the woods they were hiding the camp in.

B: The homeless were removed to make way for the trees to be removed and work to be done in this area.

I don’t see any way the homeless camp benefits Walmart or the property owner.