The thing about owning a business is you never hire someone unless you absolutely, positively need to. This apparently wasn't the case at BigCo. Maybe they're the ones that never owned a business.
Well, it's Snap, so that means they were pumping that sweet VC cash roll into headcount (like any similarly funded startup). Then one day they realize that doesn't deliver the desired growth, and they cut headcount. I've said it before, and I know it sucks, but startup layoffs are often the result of letting go of people that in a normal business probably shouldn't have been there.