Why should he not have ignored it...that type of erosion is irrelevant to his point. I repeat...the RELEVANT type of erosion is that which is evident on the TOPS of the structures, and totally unaffected by "flood erosion constrained in hard bedrock channels". That erosion is ONLY caused by long-term exposure to heavy rainfall. The Sphinx and the structures around it have such erosion. Other structures in the same area do not. The climate that would yield heavy rainfall had been well over by the time of the supposed accepted age of the Sphinx.
“Why should he not have ignored it...”
Because it displays either incompetence or intellectual dishonesty to ignore the obvious cause of the vast majority of the erosion. That might be irrelevant to you, but it’s not irrelevant to me.
“That erosion is ONLY caused by long-term exposure to heavy rainfall.”
Says one guy who seems to only be talking about evidence that fits his preferred hypothesis and ignoring other contrary evidence.