I can’t decide not to buy a house because by doing so I increase the demand, which increases prices and makes it harder for poor people to afford housing.
Not sure why you can't do that. But people do that everyday. Its a personal calculation. Look at how many people choose not to have kids because they feel the world is over populated. How many people carry garbage until they reach a garbage can. Lots of these calculations occur every day. As we become shittier and shitier people then less and less of the calculations happen. More garbage ends up on streets.
So what are my options? Suicide?
Use a job board or fair that is for you.
So I should just stop working?
You shouldn't go to a job fair for a group that you're not a part of.
So what should people do?
This is taking it to absurd lengths. Its a balancing act. A calculation that we all make day to day. Some put more emphasis on themselves. Like most people don't feel like they need to attend job fairs for women when they are not a women. When I left the military I attended job fairs for veterans. Should you also be invited to those? What about job fairs at the university I attended?
The working class should build solidarity
Entering a space we weren't invited to take away their opportunity would not be solidarity.