In Marxist analysis, as capitalism goes on, capital accumulates, centralizes, and coalesces. The rate of profit also has a tendency to fall as time goes on, and automation and productivity raise the organic composition of capital. This has a socializing impact on how production and distribution is organized, while leaving appropriation of the surplus in fewer and fewer hands. This leads to crisis. Accelerating the growth of capital therefore makes this crisis happen sooner.
The reason this is a terrible strategy is because the collapse of capitalism does not guarantee socialism. For that, you need a revolutionary party that can educate and guide the whole of the working class towards revolution, otherwise it just collapses into barbarism. Climate change cannot wait for capitalism to collapse on its own either. As the better stewards of accumulation, the DNC provides a more stable base for capitalism to progress smoothly and hit crisis faster.