The announcement-mills (phys.org comes to mind but there are plenty of others including nature.com itself) are not really "original" sources, the papers are, but such announcement-advertisement articles are submitted regularly.
Finding the freely available pre-print and/or author provided copies without resorting to (ahem) other workarounds is a pain but useful.
Sometimes people post these and others respond with links to freely available versions, or articles about the work. In such cases we're happy to update the URLs.
We're not happy about announcement mills either (and those sites are penalized on HN), but that's arguably a separate problem.
As much as I hate to admit it, the sad state of suckage for announcement mills (including university press sites) actually does have some minor advantages; which would you be more inclined to read and up-vote?
"Astronomers detect furthest galaxy yet with Keck telescope"
or
"Lyman-Alpha Emission From A Luminous Z=8.68 Galaxy: Implications For Galaxies As Tracers Of Cosmic Reionization"
Non-Astronomers would be lucky if they understand the details presented in just the abstract of the paper, and I say this as a non-astronomer who does _NOT_ understand all of said details. Reading original source papers takes far more effort than reading lightweight announcements, and this gets to the fundamental question of, "What do we want HN to be?"
The status quo of interested HN users finding and comment-linking to the original source papers (if available) on the puff-piece stories is a lot of manual work and some stuff gets missed, but it really does tend to work out reasonably well. If we forbid paywalls without workarounds and require original sources, then we will miss out on a lot of great new research. Besides infringement, there is no easy answer for this situation.