I have to say, if this is on church grounds, this really seems to cross the boundary into direct political activism, which should lose the church it's tax-exempt status. According to Federal IRS rules, in order to maintain 501(c)(3) tax-exempt status, one of the limitations is that
"it may not be an action organization, i.e., it may not attempt to influence legislation as a substantial part of its activities and it may not participate in any campaign activity for or against political candidates." That little lynching display certainly seems to fit the bill as working against a political candidate.
Not to mention the before-mentioned idiocy in that his display has Uncle Sam killing Obama when he seems to be trying to say that Obama is killing America, and the insanely inappropriate visualization of hanging a black man.