In a perfect world things like this wouldn't happen. Top employees would never leave for a better paying job, and you'd never have to let employees go to remain competitive. But this isn't a perfect world. We must prepare for the worst and hope for best while remembering to treat each other with as much respect, kindness, and understanding as possible.
Whether or not these specific cuts were needed or sensible, I don't know. What I do know is that Tesla is a young company in a highly competitive space. Were I personally to take a job at Tesla I wouldn't expect to be there longer than a year - especially if I was a temp worker or contractor. Anyone who's worked at small, early stage startup in the past would know how this story goes. You often work harder and longer than you would at a more established slower moving company, you don't get the perks, and you're constantly worrying about whether or not you'll have a job next month. But it can also be very rewarding when things go well. These are the decisions you must weigh up as an employee when looking for work.