If there are 25,000 homeless and an EMT sees 1000 homeless people in a year (which I'd say I'm probably vastly over estimating) in situations where they are in greatest need, then all you have is a limited anecdotal view of a small proportion of the total population of homeless people at the lowest and least dignified point in their lives.
It doesn't tell you how they got to be in that situation.
It doesn't show you their day to day grind.
It doesn't indicate if they always want to be homeless, or you've just seen them when they are feeling defensive or aren't in full control of their faculties.
In short, it just shows you that because of the nature of being an EMT, he sees people in dire situations, on occasions that would frustrate anyone viewing the homeless person because of any number of high stress factors, including mental illness but also malnutrition, poor sleep or severe discomfort.