I'm running Arch + Cinnamon on a Pixel 2 and HiDPI is not a problem at all. The last problem application for me as the Arduino IDE, but that has recently been fixed.
The simple fact is that after 15 years of corporate mismanagement there isn't anyone left there that cares anymore. It is really sad, when we started the sites, all we ever wanted to do was help the OSS community. But those were the days before a plethora of other alternatives existed.
SourceForge wasn't bought by VA, it was started as a skunkworks projects by 4 developers inside of VA. Once the site started to get traction is when the corporate overlords started taking notice and forcing the horrible Ads, and now crapware onto the site.
This is old news. Slashdot even did a story about this long ago. It seems every couple years someone finds this and makes a mountain out of a mole hill. If you're connected to the internet expect all kinds of random packets to be tossed your way.