SAN FRANCISCO — “Nimbyism” — the condition of taking a “not in my backyard” stance towards building — may be the biggest obstacle to housing development out there. So what better way to promote the construction of more housing units than to champion  “Yimbyism” — the condition of viewing development through the lens of “yes in my backyard?” That’s the aim of Sonja Trauss and the pro-development advocacy group she leads, known as the San Francisco Bay Area Renters’ Federation. The guiding principle of the group’s platform is that some housing, whether subsidized or high-end, is always better than no housing, she said at a presentation at Inman Connect San Francisco. Every condo that isn’t built in the San Francisco neighborhood of The Mission “is a high income p…