I've made no secret about my thoughts on this. I'm not happy about it in the slightest.
I would have been super annoyed but not quite so angry if I had been available to participate in the 3-hour event and caught a good Zapdos with TS. But (imagine this!) I do have some semblance of a life outside of Pokemon Go and had made other plans that could not be changed given the short notice we were given.
Community Days are different in that: a) we know about those well in advance and have the chance to plan around them, and b) we can save one or more good specimens so all we have to do (if nothing else) is find time to evolve them during the 3-hour window. For the record, I'm still irritated that the 100% Charizard I had previously maxed is now outclassed by a different Charizard. But there's a big difference between an irritated customer and an irate one.
I urge everyone who is upset by this decision to contact Niantic directly and let them know. I have.
I'm quite sure Niantic pays no attention to anything said on Pokemon Go sites or forums like this one. But maybe they will listen if enough of us contact them directly and let our voices be heard.