It is you who have taken Lukaszkiewicz out of context, quote mining his comment about mass graves.
Do you understand what constitutes evidence? You ask for evidence, and then you quote one of the eyewitnesses, who makes up part of the evidence. The evidence for the burial of c850,000 corpses at TII comes from;Where is evidence to the presence of mass graves inside Treblinka, which can accommodate 700,000 corpses?At least I have evidence of hundreds of thousands arriving at the camp, being killed and buried, so I can say there is at least 700,000 dead, based on evidence.
“According to the witness E. Rosenberg, who is the sole person to give 'exact' details, the mass graves measured 120 m x 15 m x 6 m, which, if one assumes a top layer of 0.5 m, gives an effective volume of (120×15x5.5=) 9,900 m2. Consequently, each grave could contain (9,900×8=) 79,200 bodies, (which agrees almost exactly with the Düsseldorf Court)
In accordance with this, if 860,000 bodies were really buried in Treblinka before their cremation, there must have been (860,000÷79,200=) 11 graves of this size, the total surface area of which amounted to (120 × 15 × 11 = 19,800 m2.”
1 - eyewitnesses who worked at the camp who describe mass graves
2 - circumstantial evidence of mass transports to the camp, without corresponding mass departures
3 - archaeological and forensic evidence of large areas of disturbed ground containing cremated remains
4 - photos showing large areas of disturbed ground containing human remains.