Publishers knew about the GDPR; there was a two-year grace period before the GDPR went into effect, which ended earlier this year. No, it's a conscious choice rooted in business.
News websites make substantial amounts of money through advertising. These ads serve scripts which collect information about users. The collection of the information isn't strictly the problem. It has to do with storage and consent.
For any company operating globally, the GDPR created two zones of consideration: the EU and the not-EU. Data on EU citizens must remain on servers located in the EU, UNLESS explicit consent by the user is provided and the data is only used expressly for the purpose was intended.
Say you link up ad networks into your news website. The scripts the ad agencies include with their ads don't ask for consent when collecting data. This is standard practice across the Internet. To comply with GDPR, a news website would have two options: scrap the ad scripts, or just don't let EU citizens on the site. The not-EU has a lot more people than the EU, so building a separate site wouldn't make financial sense. As a news organization in 2018, you also need every cent you can find to stay afloat. Subscription models don't work for every site, so you still need to provide "free" access to the site by using ads.
Considering all of this, blocking the EU is often the best option for news organizations. Not all, but some.
