Some accounts are deleting their posts after a few downvotes. It’s devastating on communities like c/asklemmy.
Lemmy doesn’t track an account’s karma like reddit. So, all downvotes will be isolated to your post or comment and won’t affect your account—unless you wrote something truly horrible.
Remember lemmy is a community effort. Deleting a post also removes all comments on it. So you are not only robbing the effort others put in, you are actively removing knowledge from the fediverse. Others won’t be able to find it through search and lemmy will seem lonelier than it already is.
That is/was generally a protest against reddit itself. To take away the free content people had given reddit and to reduce its value.
For the same reasons a lot of people moved here.
Reddit is really to blame in that case.