That would be because they sent you a deep link into the app, not a regular link to a webpage. The same thing would happen if someone sent you e.g. a link to an item on the iTunes Store, or to a Spotify playlist.
Sending the deep link is the default behavior when you hit the convenient "Share" button. The only way to share the regular web page link is incredibly cumbersome:
(1) Copy the Apple News deep link to your clipboard
(2) Paste it into a browser that will actually show you the final destination of the app link. This step is impossible to do in Safari on iOS (it will force you to use Apple News, and if that's not installed, it will force you to go to the App Store). So you end up pasting the link into say, iOS Chrome. This still prompts you to go to the App Store for Apple News, but it allows you to cancel this and just load the web page.
(3) After the link has loaded in your alternate iOS web browser, now you can copy the real article link and share it.
The above is way, way, way too cumbersome for the vast majority of iOS users to ever want to do, let alone think about. So, in a practical sense, sharing true article links surfaced via apple news is cumbersome enough to be virtually impossible for most users.
Thx, but doesn't that indicate that it's not a deep link, but a simple redirect that Apple refuses to give to me when I use their default browser—instead giving me something else?
And it's worth noting that simply clicking that link gives me the following alert:
>Restore "News"?
>
>You followed a link that requires the app "News", which is no longer on your iPhone. You can restore it from the App Store.
The two choices I'm given are "Show in App Store" or "Cancel"
Apple clearly tells me that it is impossible for me to view this webpage unless I install their News app. This is clearly false, technically, and I knew it. But I literally hadn't figured out how to view it until somebody mentioned trying copying and pasting the url into another browser.