There are lots of ways to interact with folks who don't understand something that get your point across without making them feel bad. I'm guessing you didn't employ any of those strategies.
The truth is probably somewhere in between. I was firm but polite. I was called in because I was going to be analyzing the data. Build data warehouse and import other data. I had to be firm because I know how much time it takes to clean up data before you can analyse it.