Thurston has a right to feel angry and question the NRL administration. His side just got knocked out again after dubious calls, so as a mere mortal he is entitled to a whinge.
Regarding the easy run Souths seems to be getting, and the perceived push towards a Souths v Easts final, I'm not sure the NRL would have an actual authorised and formalized agenda favouring certain teams. There may be, however, a general verbalised understanding and agreement amongst the administration that certain teams winning is beneficial to the League, which may trickle down to the refs. Who the f**k knows really!
Whatever the case, I'm hoping for a Melbourne v Manly final ;-)