In Masechet Shabbat 119b, it brings 8 statements saying "Jerusalem was only destroyed because x". Each time, x changes.
How can it say that Jerusalem was only destroyed for one particular thing - 8 times?
The eight statements are from eight different sages. Presumably, as in other places where the g'mara says "A says X, B says Y, etc", they are disagreeing with each other. Sometimes when there are multiple opinions the g'mara reconciles them (A was talking about this specific case where X applies, B was talking about this other case where Y applies, they don't disagree), but here the g'mara doesn't do that. So we are left with eight options.
Alternatively, and this is my own idea, the last of these eight statements (from Raba) says that Jerusalem was destroyed only because men of faith ceased therein. Men of faith ceasing therein would cause the issues raised by the other seven -- desecrating Shabbat, neglecting education of children (by which surely they mean education in torah), not rebuking, despising scholars, and so forth. So each of the first seven identifies an aspect of the problem but its "only" is too narrow, and Raba's "only" covers all the rest too.