I’ve seen the same kind of thing. We had a country text box on one of our forms. People would put in so many different things. I saw “USA” “America” “The united states of america”, “the usa”. Then there were also wrong answers where people put the county name “richland” “cabarras” etc.
I assume that if you had a state text box, (instead of a drop down), people would put similar things, like “Vermont”, “vermont”, “vt”, “VT”, “Verm.”, etc.
Depending on the database used (whether it’s case sensitive or not) those could be 5 different results. The problem with that is if you want to search the database by state you can’t do it easily. (To search for vermont you’d have to search for “VT” and “vt” and “vermont” and “Vermont” and “Verm”...)
Dropdown lists can help standardize all of the results in the database. That way you can search for “VT” and return all of the Vermont users, instead of only the ones that typed in “VT”