Re: I must be missing something...
"They should because the office software is part of their job. Now probably it shouldn't be that big a part, but if they insist on using Excel for their database, then they need to know how to use it for the database-style things they intend to do. Column typing is one of those things."
It's no excuse to not know about the tools you use. No chef would say that they don't know about the different knives and pans they use. No violinist would be blase about the violin they use. As a programmer I'm really fussy about my hardware, hosting and tools.
I've known that Excel makes assumptions for years. One of the reasons I try and get people using a combination of SQL Server + some sort of sql reporting tool is that SQL doesn't mess with your data. You can also set up things like SSIS jobs that will import your data in a consistent way (like filtering data or removing columns). And this stuff is cheap now.. Put it on a server and run PowerBI.