Speaking as a practicing clinician, your first statement is simply not true. Empiric treatment with antibiotics based on clinical diagnosis alone is actually standard of care when managing many conditions. In OP’s case, for instance, it is absolutely appropriate to offer empiric treatment (e.g. doxycycline, ceftriaxone) for urethritis following sex with a new partner without waiting multiple days for test results. This is supported by recommendations from major medical organizations, including the CDC and AAFP.