Confusing or misleading titles aside, YC has made literally billions of dollars off of free software and the under- or unpaid labor that produces it. They absolutely should be patronizing free software projects, perhaps not X11/X.org/Wayland, but certainly outfits like the Debian, OpenBSD, or FreeBSD foundations that make their startups possible.
Instead of laughing at ourselves for having misread a title as suggesting that YC might actually contribute something back, we should be publicly shaming them for not doing so and being an open source free-rider.
Instead of laughing at ourselves for having misread a title as suggesting that YC might actually contribute something back, we should be publicly shaming them for not doing so and being an open source free-rider.