In favour: the fact that costs of access to research haven't plummeted with the rise of the internet as they have for other media, and that the traditional publishers are making profit margins of 30-40% (typically associated with luxury brands) indicates that the academic publishing market is not working as it should, and that the traditional publishers are making more profit off publicly funded work than you'd expect them to "deserve" based on the value they add.
Against, from a societal point of view: Sci-Hub is no longe-term solution, as it still depends on articles being published elsewhere. Furthermore, there is not yet a proper alternative to the traditional publisher's main contribution: credentialing of academics.
Against, from a point of view of the shareholders of the traditional publishers: if this leads to cancelled subscriptions, they lose money. A case could be made that Sci-Hub has contributed to e.g. most German university libraries cancelling their Elsevier subscriptions this year.
Against, from a societal point of view: Sci-Hub is no longe-term solution, as it still depends on articles being published elsewhere. Furthermore, there is not yet a proper alternative to the traditional publisher's main contribution: credentialing of academics.
Against, from a point of view of the shareholders of the traditional publishers: if this leads to cancelled subscriptions, they lose money. A case could be made that Sci-Hub has contributed to e.g. most German university libraries cancelling their Elsevier subscriptions this year.