He is a Prominent figure so twitter would have helped him get this handle. It's not unusual, not long back i too tried to get back several handles with trademark names from not only twitter but from other popular places as-well and it did work as people fear legal repercussion and twitter like big brands do respect legal stuffs.
Also twitter clearly forbids handles with trademark or misleading names,
Using another's trademark in a manner that may mislead or confuse others about your brand affiliation may be a violation of our trademark policy. - Trademark policy.