Your statement 'there are some really dumb people out there' could also be phrased as 'there are some really smart people out there who have better things to do than surf the Web all day' and just want to get to the information they are looking for without having to decipher an interface.
When you have to "decipher" the difference between "submit" and "submit your application", smart is not a valid descriptor.
edit: I guess I should state that I'm describing the submit button on an actual form, with the title "application" or some such and that the user is entering in data (a lot in this case) and that "submit" is pretty much industry standard for forms
