A union has legal obligations 767, and ignoring those obligations in favour of something you happen to agree this time doesn't mean you will agree with it the next time. It's called "duty of fair representation" and is enshrined in Labour Law for a reason. Read it.
"A trade union or representative of a trade union that is the bargaining agent for a bargaining unit shall not act in a manner that is arbitrary, discriminatory or in bad faith in the representation of any of the employees in the unit with respect to their rights under the collective agreement that is applicable to them."
If you recall CUPE is doing the exact opposite of what ACPA is doing based on three independent legal opinions, each stating that CUPE would be subject to DFR complaints if they did what ACPA is doing. Why would anybody be surprised at the DFR complaint against ACPA, and how smart is it in your opinion to keep bashing our heads up against the law?