I know it's easy to pick on the dirty school psychologists, but they're just following the law. When working in a school, and therefore for the local education agency, and they are not licensed, they cannot DIAGNOSE.
What they can do, however, is CLASSIFY a student for special education services based on one of the thirteen disability categories outlined in the Individuals with Education Improvement Act (IDEA). One of those areas is Specific Learning Disability (SLD) and the language of the law does not state use the term dyslexia. Rather, it outlines 8 acheivement areas. The ones most closely related to dyslexia would be basic reading skills (i.e., dysphonetic dyslexia), reading fluency skills (dysfluent dyslexia), or reading comprehension.
You would be surprised how much a school psych does. They're not lazy.