I'm gonna be honest with you, I dislike the attitude of "I never understood sth" followed by confrontational and accusational language. Maybe you did not intend to be hostile, but you're much less likely to get a straight answer with that tone. You're much more likely to trigger "I know, right!?" responses by people already sharing your opinion/impression.

Seems like you already made up your mind about lurkers apparently. Let me tell you why I mostly lurk. I guess this applies to others as well.

• Just because people don't engage on social media does not mean they don't engage in other parts of life.
• Engaging takes effort, time and energy. Many people don't have those to spare.
• Contributions are also is not guaranteed to get positive feedback. Discussions with people holding different opinions is difficult for some people (various reasons). Open hostility is also a possibility.
• Some (I guess most) people are not here to have discussions at all, just to consume. They are not primarily looking for a community, but entertainment or news. They have other priorities / more important things to do.

Maybe you actually were interested in an honest answer. Here it is.