The layoffs occur while Uber merges its Eats platform with Postmates. Although there is still a distinct Postmates app, it will run more and more with Uber Eats technology. There is simply no need to have so many team members supporting Postmates, however unfortunate the number of humans.
There is also the simple question of survival in the current climate. Uber was already cutting costs before the pandemic, and the virus only worsened the situation when the demand for rideshare fell. The company recently sold its autonomous car and flying taxis divisions in an attempt to cut unnecessary expenses. Add consolidation among rivals, like Just Eat’s acquisition of Grubhub, and Uber faces particularly strong pressure to cut its spending whenever possible.