Conversation so far:
What was his Thích Quảng Đức's religious background?
Thích Quảng Đức's religious background was Mahayana Buddhism.
Was most Thích Quảng Đức's country also buddhist?
The religious composition of Vietnam at the time estimated the Buddhist majority to be between 70 and 90 percent.
If the Vietnamese buddhists were the majority, then why were they being persecuted?
President Diệm was a member of the Catholic minority, and pursued discriminatory policies favoring Catholics.
How did the people react to President Diệm pursuing discriminatory policies favoring Catholics?
Many switched to Catholicism to help their own careers, and the remaining Buddhists were discontent.

Question: So did Catholics then become the majority?
Self-contained rewrite: So did Catholics then become the majority in Vietnam?