This is true, and likely reflects my own biases (and other people who have worked on the game) as UK-based white atheist people in the late forties or early fifties.
The game is likely filled with small biases, but the real problem is that it cannot support the infinite complexity that real life represents.
For example, the idea of gun ownership being liberal is true in some countries and very much NOT true in others (including my own). The idea that religious people oppose prostitution, or contraception varies dramatically depending on the country AND the religion.
The thing to remember is that the voter GROUPS are strong extremes, whereas actual voters only take partial influence from them. Someone with 100% religious membership is likely a preacher, people with 10% religious membership probably rarely, if ever, go to a church/mosque.
So when we have effects in the game that make what may seem like fairly cliched or extremist connections, for example between religion and gay marriage etc, we are hopefully only representing the extremes.
Its a VERY difficult subject, and it happens throughout the game. People only really notice it strongly when it applies to groups they themselves identify with. For example I’m a liberal, but I support both CCTV cameras and restrictions on handguns. The game is wrong from my POV, but I try very hard to have it take a global view.
Note that we CAN make country specific group changes. For example in the UK, religious people are altered so that they do not mind gambling and are not so bothered by gay marriage or stem cells.