Tech Is a Citadel. Del Seymour Built a Drawbridge.
SAN FRANCISCO — On his walking tours of the Tenderloin, a historically seamy neighborhood named for a cut of beef, Del Seymour passes Boeddeker Park, now a verdant jewel of urbanity. Eleven years ago, it was a notorious hellhole where Mr. Seymour, then a crack addict, dealer and pimp, shooed away do-gooders from the local…