Peace with non-fundamentalists terrifies the fundamentalist because to them, being Christian doesn't mean just being 'good' - it means being 'better' than others. Being better that others means having to see them as enemies - and making war on them. The fundamentalist views not being allowed to make war on their enemies as oppression of their faith, or defeat.
The religious right sees every group trying to achieve equality with them as a threat, because if they become equal to them, THEY won't be able to abuse their human rights anymore. Giving other people equality WITH THEM, in their minds takes something away from THEM - POWER - and that TERRIFIES them. It scares them shitless.