Regarding teachers' strikes, often times teachers strike for stuff like smaller classrooms which are beneficial to students.
Regarding strikes in general, it essence it's telling working people to suck it up. Not much different than 100 years ago when one was told If you don't want to come to work on Sunday, don't bother coming in on Monday.
FWIW, I think there are ENORMOUS issues with some of the municipal contracts that were negotiated in the past. I especially despise the whole double dipping in which employees are allowed to retire after 20 years with full benefits.
However, I also think that a system which funds important local services like schools, libraries and police on the basis of property taxes is fundamentally flawed.
Some days I pray for Silence, Some days I pray for Soul,
Some days I just pray to the God of Sex and Drums and Rock 'N' Roll.