Because I have a moral objection to people being taken advantage of or conned.
If I came up to you or a member of your family while someone was trying to con you out of money and just proved to you it was a rip off at no benefit to myself, I refuse to believe you would be so indifferent about it.
Although I have to admit, after reading some of the hand wringing and spineless antics of some members a lot of you would probably go back and bend over for it anyway.
How is a family member being conned even remotely comparable to Joe Public getting turned over? It's a deliberate (and painfully blatant) emotional misdirection.
If that's the best sales line you've got it's no surprise he's hammering you!