New development lowers overall housing prices in the surrounding area, but forces the people who live in the affected neighborhood to relocate, either directly or because they're priced out of the neighborhood by gentrification. It's entirely rational that the people affected by this would be against it - they get no benefit and have to pay relocation expenses and uproot their lives. The beneficiaries are the new occupants, the developers, and the landlords.

Which means far left NIMBYs have always been strange to me. The far left already rejects landlords and rent. The problem goes away if you remove rent from the equation, because the owner/tenants of a building get to decide whether to sell it for redevelopment, and get to capture the sale value if they do. So if there's already a solution embedded in your ideology, why go out of your way to blame the concept of development itself?