Her organization was a cult. Her works of charity were just a front for recruiting people to her ideology.  And what was her ideology? She refused funding offers from U.S. President Ronald Reagan  yet she accepted funding from criminals . These funds were assuredly stolen money.
She was a very dark soul. In her own words:
"...Even deep down ... there is nothing but emptiness and darkness ... If there be God—please forgive me. When I try to raise my thoughts to Heaven, there is such convicting emptiness that those very thoughts return like sharp knives and hurt my very soul ... How painful is this unknown pain—I have no Faith. Repulsed, empty, no faith, no love, no zeal, ... What do I labor for? If there be no God, there can be no soul. If there be no soul then, Jesus, You also are not true." Did I convince you that Mother Teresa could have been a terrorist? Maybe? Just a tiny bit?
Of course I'm neglecting quotes like this (and about 1,000 others like them):
- Peace begins with a smile.
- If you judge people, you have no time to love them.
- The hunger for love is much more difficult to remove than the hunger for bread
- If you can't feed a hundred people, then feed just one.
- If we have no peace, it is because we have forgotten that we belong to each other.
My point is, first "see the good". If all you hear, read or learn about something is negative, yet is still has an abundance of supporters, it deserves a fair investigation. Politics and religion come to mind. So do neighbors, coworkers, family members, and anyone not like us.