"I don't think your clients belong in jail, but I don't get to make that decision! I represent the government of the United States without passion or prejudice,"
guess what movie this is from?
basically, your job as a physician is to treat the patient in front of you with the same standard of care. you may not agree with their lifestyle and you may not feel sympathy for them or their condition, but you MUST treat them and as roja put it, "If you can't check your own morality at the door and it endangers a patient's life"
as a GI doctor, you're going to see people who abused alcohol and/or IV drugs for a large portion of their life and now have cirrhosis and hepatitis and need their abdomen tapped all the time.
in ALMOST ever speciality, you will see people who have made decisions in the past or present that have compromised their health and/or the life of others. as a physician, you cannot spend your time judging individuals. your DUTY is to treat.
as stated earlier, as an ER physician you ARE your patient's strongest active. many of the individuals we are referring to have no primary care, access to primary care, etc and come to the ER for their medical care.
finally, to the OP, if you are looking to practice in a nice suburbn setting (which will not make you immune to the homeless and intoxicate), you will likely see fewer than in an inner city, county ER. however, realize that most training programs are in urban areas because these are the ER's where you will see sicker patients and trauma patients.