Agree, this is not the disaster you are making it out to be. The affected passengers will be placed on other flights. They just may not be the nonstop flight they originally booked.
Why are many of these flights being cancelled? One big reason is staffing. Airlines don't pay enough, work schedules can be terrible and many passengers treat agents like garbage. I can't tell you how many times over the last several months, passengers have stormed into the office where I work, acting like frustrated two year olds.
We aren't responsible for delays/cancelations/staff shortages/weight/the stuff you leave on planes, etc. Most agents do their best to help you, but honestly, if you treat them terribly, do you think they will go out-of-their way to find a solution?
The corrections in the schedule will actually help bring some stability, hopefully resulting in less problems this summer. Last summer, staffing combined with weather, made it a nightmare many days.
People always sing the praises of foreign carriers (vs. US), and many times they are great, but not so much when you run into a problem. IMO, try getting help from Avianca, or Copa, if there's a problem with your flight, just to name a couple.