>Bullshit. You're committing the fallacy that comes from Marxist thought--- that one's position/class/socio-economic-factors are the determining factors in their values and beliefs. People are not so simple, their thoughts can come from elsewhere. You're wildly underestimating the sentience of these people.
People's values and beliefs usually model the reinforcement signals they've actually received, not the distribution of all such signals that a human being in our world can receive.
So yes, their values and beliefs will tend to support their interests. That is, after all, what values and beliefs are for.
This is a bit reductionist. One popular example I see on HN/Reddit is when someone is supportive of market capitalism you often see this dismissive comment in response:
> "Every American think's they are a future millionaire and from this delusion they blindly defend the rights of millionaires to their own detriment."
This sounds clever but it's based on the (fallacious) assumption that everyone's political position should be reflective of their current economic status - or that the government's economic policy should be defensive of one's current economic status - and not doing so is acting against your self-interest.
But it's entirely possible to support a political position that is advantageous to people outside of your own short-term direct self-interest, because you see it as the most beneficial to the most amount of people in the country - and ultimately to yourself, family, friends, and country in the longrun.
Self-interest is often falsely perceived to be merely only about benefiting one's current direct/personal circumstances. Given that:
a) we're social beings
b) we all must live and survive within communities over an extended period of time
a natural side-effect of any one's self-interest within a economic/political system must itself factor other people's interests and external realities.
The exception of course is when an economic/social system attempts to reduce everyone to one imaginary class of people, and a singular self-interest - which is where the Marxism analogy comes in (which opens up another can of worms).
People's values and beliefs usually model the reinforcement signals they've actually received, not the distribution of all such signals that a human being in our world can receive.
So yes, their values and beliefs will tend to support their interests. That is, after all, what values and beliefs are for.