Offsets cause other issues, such as when two parallel routes are deemed as separated ONLY if everyone is on the centrelines, traffic getting too close to Danger or Restricted Areas etc.
Oceanic is different, offset is acceptable.
As for the incident, it is still unclear who, if anybody, actually got an RA, the divergent headings may have just generated TAs.
For the ATCOs, if someone requests a level and it's not immediately available, don't mention the level, just give them a quick "rogering" !!!
For the pilots, always follow TCAS and ignore ATC, it will save your life.