If Racism is defined as “hatred or intolerance of another race or other races”, then we should define Religionism as “hatred or intolerance of another religion or other religions”.
Perhaps, the above helps us see clearer more than a narrow focus on religious zeal, jumbled up by descriptions such as “excessive and exaggerated” or “affected and pretended”.
Zeal turns our attention inward, while hatred or intolerance are outward expressions immediately felt by the person before us. We don't have to ignore zeal and its sister, passion. But, addressing hate and intolerance seems to be a better starting point.