Why Leave Harry at HW at the End of HBP?

[Gregory Sopko]

No: HPFGUIDX 148332

  Mauricio:
  DD´s wisdom will be available at Hogwarts. His
  portrait is at the Headmaster´s office. I wonder if
  this will be a link to him in the 7th book and if
  Harry really needs to leave Hogwarts in Book 7?

Gregory:
I think Harry will spend sometime at Hogwarts despite what he says 
at the end of book 6, but his pursuit of the horcruxes will take 
him away for long periods of time much the same as it did for DD.