I think you did the right thing. As a grownup, I absolutely hate it when somebody takes it upon themselves to lecture me. Not that I don't always have more to learn, not that I don't make mistakes. But I notice that a lecture simply leaves me feeling angry, defensive and frustrated.
One example: recently in a morning discussion group, one participant brought donuts, a very rare treat for me. Because I have diabetes, I can't eat a whole one, but I took one on a napkin, broke off 1/4 to eat, and offered the rest to my husband, who shook his head, and then to a new guy on the other side of me. He muttered, "Don't want it all; don't take it!" and I was instantly feeling outrage and hurt. He doesn't know I have diabetes, he doesn't know how carefully I eat, he doesn't know that I've lost 18 pounds in the last few months, he doesn't know that my husband is a dependable food vacuum, except this time. I've forgiven his righteous comment, because he's young and slim and still thinks he knows everything. But a polite "No thanks" would have done the job.
The man you describe was genuinely rude, probably unnecessarily so. And I can understand his wish to not face the frustration of trying to communicate with a person with a strong accent. I may be verbally stupid, but I sometimes have trouble conversing with U.S. citizens from the deep south, and with inner-city blacks, and with folks with strong Latino accents. I have actually given up on a few phone conversations with call centers in India, simply because no amount of repeating gives me a clue about what they are saying. On the other hand, I am willing to at least try. But it does leave me feeling like the dumb one if it doesn't go well. Perhaps that customer had been in the same uncomfortable position a few times too often. You can't possibly know what all was behind his request. He could simply be a demanding and privileged SOB, or he could be a guy who felt intimidated by the possibility of failure. Some people, particularly men, are not willing or able to go there.
So, I notice that this response can easily be interpreted as a lecture to you, KansasMom. I hope you'll understand that's not my intent. I just want to give a feeling-sense of what else might be going on when somebody appears to be just rude.