At the end of the parsha in 20:23, Hashems warns them to make a mizbeiah but not to make steps, "אשר לא תגלה ערותך עליו" - so your nakedness should not be uncovered upon it.
Rashi tells us that despite the fact that it is not really erva because the Kohen was wearing pants under the robe (gotchkas of sorts) but it is similar to gilui erva.
People sometimes hear things that make them uncomfortable. They then look for ways to disassociate themselves from those statements, in order to remove the guilt. One of the ways of doing this is by saying that the comparison is not valid for reasons x, y and z and therefore the lesson is not valid.
I recently wrote some articles, among others, in which I made comparisons to derive certain lessons. It is true that the items compared are not 100% exact. They rarely are. Yet, I felt, the lessons are valid, at least t consider and think about.
Yet, people find ways of saying the comparison is completely invalid. That way they do not have to consider the ramifications of such lessons.
We see here such an approach of making lessons is completely valid. The Kohen was not exposed over the stones. He was not shaming the stones with his nakedness. After all, he was dressed. Yet the Torah still considers it as if the Kohen was shaming the stones, just because it was similar.