"In the latest teacher strike in Los Angeles, the nation’s second-largest school system, some 30,000 teachers walked off the job saying unchecked growth of charter schools and charters’ lack of transparency and accountability have become an unsustainable drain on the public system’s financials."
That's odd. The union's own release[0] states no such concern (beyond an offhand mention to charter co-locations in bullet point #5 of 7).
[0] https://www.utla.net/news/utla-will-strike-monday