According to scripture, you, as a Christian, have no responsibility at all for trying to take the world and retrofit it for paradise. The Corinthians mistook something the apostle Paul said in much the same way many do who attempt boycotts of secular companies. Paul had to set them straight in a subsequent letter and in quite forceful terms. And what he went on to tell them to do is something that too many Christians are unwilling to do. Why? It's easierr for folks to organize boycotts of secular companies and call that spirituality than to tell people they know who call themselves believers to change their ways or get out.
I don't care who shops at Wal-Mart, Target etc
the only issue of concern is "same-gender clout" a store is given, so if people choose not to shop at a store who they feel is deliberately undermining and make a mockery of the institution of marriage.
Nothing more!