I agree with you. At some point, you have to let them say what they say and leave at that. As Jesus said, "Do not give dogs what is sacred; do not throw your pearls to pigs. If you do, they may trample them under their feet, and then turn and tear you to pieces" (Matthew 7:6). Of course, Jesus was known for not letting others draw Him into arguing. Whenever someone took issue with Him and tried to trip Him up, He would simply turned their own arguments back on them. Most of the time, they didn't even know how to respond afterwards. That still works today, too...but like those in Jesus' day, they'll probably just walk away upset and ready to kill you.
Greg C
http://www.geocities.com/greg_pc/