I've been engaged with Postgres community for over 20 years now, and this has been my experience, too, throughout that time. Off and on I have interacted with a few other large projects, and nowhere (except at CodeBlocks) have I found such a welcoming and responsive community. The CodeBlocks IDE project has been one exception where I felt welcomed; but my interaction there was quite limited, and spanned over just a few days, so I can't extrapolate too much from that.

BTW, the Postgres community is also quite protective of their culture, so I expect this welcoming nature of the community to persist for a while.