Need it take 7,500 people to run Twitter?

I think they mean you need a lot of staff to monitor and moderate for dangerous/illegal content on a global platform. Elon will just call anyone who shit posts so that won’t be needed apparently.

Facebook became available in Myanmar in 2011, but they didn't have anyone who could understand the local languages, so they had no idea what's happening on their own platform. The government and Buddhist nationalists basically overtook Facebook and started fueling the flames against the Rohingya people, which was followed by an ethnic cleansing. More than 700,000 Rohingya had to flee the country, 25,000 were killed and 18,000 women and girls were raped.

Facebook played a determining role in the genocide, which they later admitted. They not only allowed it, they amplified it as their algorithm took hate speech as engagement and started pushing it, basically turning Facebook into the perfect propaganda machine for the Myanmar Armed Forces. It didn't help that by 2016 most Burmese people have considered Facebook as their primary news source.