Is that an actual law though or just a breach of Ts&Cs. The copyright claim sounds like a bit of a grey area to me, as unlike physically downloading media, streaming you only have access whilst whoever owns the subscription continues to pay. Which also makes the point of artists missing out on potential revenues a bit of a moot point.
Most families tend to each sub to a service and then share it. So amongst a family you might have 4 subscriptions. As opposed to a family only purchasing 1 subscription if sharing was prohibited.
It sounds to me like the typical complaint about wanting more revenue from streaming services. If they weren't so fragmented or overpriced to start with then people wouldn't be against not sharing.
There's a good argument that it's infringement via communication to the public (s20 Copyright Designs and Patents Act) in that, by sharing your subscription, you are allowing a "new public" (i.e. people who are not themselves subscription payers) to access the material. Similarly, further to the Filmspieler decision in 2017, there's a good argument that anyone accessing such streams is also infringing (see eg
https://ipkitten.blogspot.com/2017/04/filmspeler-right-of-communication-to.html).
This has been a criminal offence for years (s107(2A)).
The article referenced in the OP isn't talking about any change to the law, it's just pointing out that there's a campaign to make more people aware of the law (and, I suppose, possibly indicating that there's going to be a crackdown on offenders, although given that the police are struggling to deal with more serious crimes I'm not quite sure how anyone expects that to work).
There's a lot in that article which is misleading (or arguably incorrect), particularly this sentence:
handing your password out to people you don’t live with is often another matter, although extrapolating that (e.g. Netflix merely describes this activity as being “unauthorized” or “not allowed“) to something that is overtly “illegal” and a “potential crime” seems like a very low bar to be setting for criminality
At the most basic level, if you access / use copyright material without authorisation, you're infringing copyright. When you use Netflix, they negate that copyright infringement by providing the account holder with a licence, on certain terms. If those terms say that the licence extends to (eg) the account holder's housemates or family, then there is no infringement should those people access the account. Conversely, if such sharing is "unauthorized" or "not allowed", there is no licence or authorisation to offset the infringement. Therefore, there is infringement.