Rather, the problem lies in the very hope that an answer to this question can be given and hence in the question itself. So, as for me, I would not ask whether lectures are good or bad for you. I would ask about the place that specific ways of managing teaching and learning have in the educational environment in relation to its goals. By qualifying the question, I would hope to arrive at an answer which may be more meaningful as it would push me to reflect on the various angles and implications of the potential solutions which may be invented. Specifically, in re to lectures, this allows me to escape the trap of organising the learning environment in ways that it is done traditionally and seek ways which together can be exploited by learners in a fashion which is meaningful to them.
Teacher is always one such a source.
But even the teacher is not an independent viewer.