Assalamu Alaikkum
Be self conscious of your own actions and iman, why the need to judge others?? Sometimes we are so concentrated in others that we become hypocritical because we forget our own faults! If there is something in your deen that you are doing correctly, then it's ok to help others in their deen by reminding them of how and when to do these actions. So if these people are sinning publicly and you cannot say anything to them, then you should remove yourself from their presence. If these people know you, they will ask you what's wrong and you can tell them at that moment. Or if you are around people who are gossiping for example, you can say something as a reminder like "We shouldn't talk about this person because only Allah knows, and we don't want to be punished for saying something wrong about them" or you can make excuses for the person they are talking about.
Judging is ok at times and bad at others. I think Allah allows us to judge to a certain degree as long as we don't become arrogant and look down upon others. We need to judge others to get an idea of who we should be around, who we should refrain from, who will help us in our deen, who will be safe for us, who is in need of help, etc.
As for lectures, well start out with little clips of lectures. If you like it, then find the longer lecture and listen to it. Keep searching for someone that you'd like listening to.
Here's an example of a short entertaining clip:
fi aman allah
w'salaam