And how come nobody is putting the "blame" squarely where it belongs here?....on TCAS. In this case TCAS created a conflict and possibly put two aircraft in dangerous proximity and nothing/nobody else. Generally, I'm a fan of TCAS but no controller familiar with it can honestly say it doesn't have a major flaw as this case clearly points out. There are hundreds of documented cases in the US alone where a climbing/descending IFR aircraft assigned 1000 feet above/below other IFR traffic initiate RAs on both aircraft, let alone when a VFR aircraft cruising at a VFR altitude is involved with an IFR and there is only 500 feet. Sounds to me like the controller DID do his job properly from the info provided. Anybody saying that he didn't is making other assumptions based on info not given in the initial posting.
So also be aware of:
1) Pilots that don't know the rules of the country in which they are operating,
2) Pilots that don't follow the recommended climb rate during the last 1000 feet of assigned altitude, and
3) TCAS. (Ask the engineers & they'll say "working as designed.)