Why would doctors refuse to help me reduce and aim to get off antidepressants? they won't explain & just tell me i'll be on them the rest of my life

Not necessarily ...: If you suffer with a clinical depression , symptoms may be fluctuating - " bad and good days" but you may never be completely free of symptoms ! in such case in may be wise to stay in some degree of medication for pronged time! in the other hand if depression is situational ( bad circumstances )- you may need to be on medication temporarily - it is good consult your md how to " tapper off".