Promised to protect the park, but now it's a new residential site? Residents protest, saying "You're taking back what you promised"

Promised to protect the park, but now it's a new residential site? Residents protest, saying "You're taking back what you promised"
n.news.naver.com
The government's August 13 housing supply measure selected the Yeomchang Park site in Gangseo-gu as Seoul's only new public residential site, sparking intense backlash from residents. Yesterday evening, the first public briefing was scheduled to be held, but residents gathered in front of the venue to protest.
I mean, they elected the current district head themselves, so why are they acting like this?
It's as if they didn't see this coming.