Tafsir of As-Saffat 37:30

(And we had no authority over you) — that is, no coercion or dominance by which we could strip you of your free will.

(But you were a people transgressing) — exceeding the limit in disobedience, choosing it, and persisting upon it.

This is a secondary, concessive response, assuming for the sake of argument that they [the leaders] had misguided them; it clarifies that they did not force them toward it, but rather invited them to it, and they responded by their own choice because what they were invited to coincided with their own desires. It is also said: the entire statement is a single response, the essence of which is that you [the followers] characterized yourselves with disbelief without any compulsion toward it.