Jinchurikis were always ostracised from the society for the way they were born (having the tailed beasts sealed within them). No talking, no touching, always looked down upon.
With so many barriers, they always had to work harder than others to "prove themselves."
2. Violence was perpetrated against them by Senjus.
3. #Tobirama's inherent hatred for the Uchihas. Isolation he subjected them to.