So, according to the strict definition used by ICAO, I'm not sure that a 'direct to' clearance is vectoring.
I agree, and it's a slightly worrying ambiguity of responsibility.
I remember chatting with a procedure designer after the
Cali crash. He expressed a view that crews from US flatland were so accustomed to direct clearances that it made them quite complacent of the issues associated with off-airways flying in places where it can kill you.
I'd be very interested to know whether ATC has responsibility for terrain clearance in other states on a "direct to" clearance, particularly if that is initiated by the flight crew.