"By algorithm" can be easily defined.

The easy benchmark to setup can easily be, that any feed that displays the data in a way other than the following is considered an editorial choice and thus the platform is liable as a publisher:

1. In a chronological order, and only filtered based on user selected options.

2. In any other order explicitly selected by the user.

An exception can be made to allow filtering out content that violates the platforms terms and conditions.

Alternatively there can be no exception, effectively making these platforms unworkable. This is also a choice. We do not need these platforms, including this one.