This is a really good tip. Once you start contributing to these sites the dopamine spikes from replies, likes and even debate goes up substantially and pulls you into its clutch.
Without active accounts, these things become consumption only which is easier to pull away from.
HN is the only site I feel ok giving my content too.
The big one is it makes it more attractive to your friends. There is no way to turn off Messenger if you have an fb account, so your friends will tend to message you there, and the more friends they have easily accessible in one place, the more likely they are to a) sign up, and b) stay accessible there, which perpetuates the cycle.
You have to delete the accounts so your friends can't reach you on the surveillance/censorship platforms! Otherwise they will use them and continue to use them.
Without active accounts, these things become consumption only which is easier to pull away from.
HN is the only site I feel ok giving my content too.