ירידת הדורות ט

The גמרא discusses the various reasons for the destruction of the משכן and בתי מקדש as well as the level of severity of each. It is interesting to note a nuance in this discussion which is not discussed explicitly. There is a definite progression in the "literal" nature of the critical offenses. 

Let me explain by starting with the בית שני. There we are told that שנאת חינם was the culprit. As we all know, it was pure, unadulterated שנאת חינם.

The בית ראשון was because of the ג' חמורות. But what exactly was the גילוי עריות? The גמרא explains that it refers to immodest conduct on the part of בנות ישראל. They conducted themselves in such a way as to incite the יצר הרע. It stops well short of stating that actual ג"ע was rampant.

The conduct of בני עלי in the time of the משכן is yet an even more far-fetched classification of גילוי עריות. What I believe this nuance is indicating is the degree to which הקב"ה is מדקדק throughout the generations. The generation of משכן שילה was on a much higher level and therefore judged with much greater scrutiny, ultimately being punished for something which only remotely resembled גילוי עריות. As the generations progressed, more explicit transgressions were needed to mete out justice.