In my opinion when someone say "religion has caused problems" I would say they refer to a few limited problems that some religion have perpetrated and defended (though that they might not have created per say). Namely the following.
A sexual morality based on a purely and reductively utilitarian view of sex, a hierarchy and segregation between gender, a rejection of any non-heterosexual and non cisgender sexual identity or practice and misgogyny.
A rejection of democracy or republicanism where decisional power comes from the consent and assent of the population and where power is accountable toward the population.
A form of national and mystical tribalism associated with some religion (the we are the chosen people and the others are lesser being sort of idea you can find in some religions or sub-sect of religion).
Are those problems unique to religion, not really? Has religion played a major role to defend, exalt and enforce such values? definitely. Would the world be better without the pressure of organised conservative institution actively supporting those values? Absolutely.