Every individuals had the right to belong to any religion or ethnic group they desire.
Using Nigeria as a case study, these terms politics, ethnicity and religion are use interchangeably because in practice they are the same.
Religious bodies are not different with political parties because they are fused together.
All the corruption, money laundering, killings, kidnapping, unemployment, poverty and political instability are caused by bringing religion and ethnicity into politics.
The word you are looking for is tribalism.
Religions, ethnicities, linguistic markers are just innate human desires to belong to a tribe.
It forms the basis of how one mentally divides people into heterogeneous groups.
This always leads to social conflict.Religions are followed by the vast majority of the human population so people will have an unlimited source of reasons to hate others.
Both within and outside of their own religions. Look at the Christian, Jewish, Muslim denominations.
The followers of each denomination would tell you they are following the 'right' version of their religion. LOL.