Bill D
The 2 examples of bad things christians do.

"consider sending missionaries to primitive cultures and trying to sell them a new religion and a "savior" is not only bad, but borders on dangerous"
That's OK. They don't do that.

Justifying wars and ethnic cleansing?
I can't think of any examples, although religion is often wrongly used to label different ethnic groups in ethnic conflicts, e.g. N Ireland, Yugoslavia.
Which cases were you thinking of?

(Oxfam in Sudan. They have been supplying food, water and sanitation to 600 000 refugees.)