OK, so why did they kick out the Salvation Army bell ringers?
The problem is that Target has a no soliciting rule on their premises. They made an exception for the Salvation Army, but other organizations threatened to sue them if they continued selective enforcement of the policy. Target either had to allow groups like the "Gay and Lesbian Save the Whales and Trees to Prevent Gun Violence" society or enforce the ban uniformly.
I would have been tempted to fight it out in court, but then I'm not the CEO of a multi-million dollar corporation with a lot of stockholders to answer to.