Conversation so far:
What was his religious background?
Buddhist.
Was most of the country also buddhist?
the religious composition at the time estimated the Buddhist majority to be between 70 and 90 percent.
If they were the majority, then why were they being persecuted?
President Diem was a member of the Catholic minority, and pursued discriminatory policies favoring Catholics for public service and military promotions.
How did the people react to this?
Some Buddhist villages converted en masse to receive aid or avoid being forcibly resettled by Diem's regime.

Question: So did Catholics then become the majority?
Self-contained rewrite: So did Catholics then become the majority in Thích Quảng Đức's country?