a quick hint on opening constructive dialogs with Christians

Don't label Christian communities with the words "tribe" or "tribal", or else be careful to reapply the same words to other communities, too. Insinuating that people can't think for themselves but rather that they have "tribal" beliefs that they defend as members of a "tribe" is simply not an effective way to reach them. Any social group usually has shared beliefs that are intrinsic to the group's very existence. One may as well state that the American Dental Association tribe has zealous beliefs about oral hygiene. People with that "tribal affiliation" will take a stand against those who question the "tribal laws" for combating tooth decay.