These are called random glucose tests, and they, too, can be used to check for diabetes and pre-diabetes. Because the meal before the test is not standardized the range is quite large, but that doesn't mean they don't have any diagnostic value.
An abnormal result will probably mean a fasting glucose test is then ordered. So why not do that in the first place? Without knowing the story of the pictured result, probably because diabetes diagnosis wasn't the point of the blood tests, and the glucose test was just one of several tests. In that case, doctors might decide it's unnecessary to tell the patient not to eat just because of that one test. Especially if the blood drawing doesn't take place in the morning.