Huh? Those are two vastly different groups. You can't not comment or post AND complain about it. Those who complain are those who comment and/or post. Those who lurk either don't interact at all or upvote/downvote only.
They lurk and then they complain if that makes sense. They only seem to do it if asked what they think about Lemmy though so at least it's not everywhere. Usually people who were banned from Reddit and linger around her till it runs up or people trying it for the first time and disappointed no one is talking about movies or something so they can't just get involved in a vibrant conversation.
I encourage them to get involved too, post what ever they like, to leave a comment nomater how insignificant it might seem. I get no response what so ever from them. I even make the point that reddit was this small at one point but it was the community that grew it.
What sucks is that on most social media platforms about 10% of users make the content that draws people in. The rest are typically lurking and contributing little to platform growth but are still important to platform monetization. Not important to Lemmy but still.