Oh in a pickle how arrogent. I assumed... rightly or wrongly....
I always complete in block and have never discriminated against anyone who did by assuming they were incapable of writing legibly. Spelling is a far more telling.
Block shows that you want to be clear about what you are saying and as handwriting is such an individual thing can't always be read by everyone else. Also the spaces aren't always big enough to fit large handwriting in anyway. Why do you think doctors now have printouts of prescriptions.
Unless the job you are going for requires you to be able to write legibly and clearly ect you should fill out the forms in the way you are most comfortable.