just a.kid with too much time on their hand probably, they do it exactly because it's easy to do and causes a lot of annoyance, was the same with IRC in the 90's
Phase 1: cause netsplit. Phase 2: join empty channel with ops on split server. Phase 3: wait for netsplit to resolve, deop all other ops and take over channel. Until networks build advanced channel registrations. Feeling all nostalgic now.