Reply #42: You can simply say you're not interested. Or you reply with a change of topic,

[struggle4progress]

and attempt to discuss (say) football with the person. You can pretend you didn't hear a word they said. You have plenty of options. Personally, I prefer not to be needlessly unkind or rude to people, so they generally get a short conversation from me, in which I try to take the other seriously as a human being but with the subtext "I am probably not going to be persuaded by what you say"