I would be cautious about viewing any Lemmy.world communities right now, and the Beehaw admins should make sure their credentials are locked down in case they get targeted next.
Just because Beehaw is defederated from this instance, that does not mean that visiting a recently compromised server will not cause your credentials to be compromised.
Read the post again. It was specifically mentioning viewing lemmy.world communities, which is not possible through beehaw.org due to defederation. All you would see is the content before defederation.
If done via hacked admin credentials, this is a great advertisement for enabling 2FA anywhere it's supported. AIUI Lemmy is also getting support for this for user accounts soon (https://github.com/LemmyNet/lemmy/issues/2363)