“known by scientists for a long time” doesn’t necessarily mean true. Medical science believed in the four humours and thought most disease was caused by an imbalance in bile, blood and phlegm for like 1200 years before being replaced by the idea that it was actually miasma and stinky air.
Germ theory’s claim that tiny monsters are eating your insides, maybe like invisible poisonous insects or miniature demons and you need to wash them off your hands - Sounded Batshit crazy by comparison.
Questioning long-held assumptions and challenging scientific norms is a good thing, but every human has a grift that they’re vulnerable to and for some people, even smart, sciencey people, that grift is conspiracy alt science anti vax flat earth hollow earth aliens built the pyramids and the government doesn’t want you to know the truth.
What about their handling didn’t you like?
It sounded like they were put in a pretty crappy position by the upstream adding a grumpy warning message. It’s also not like they were shipping a dangerous vulnerable old version or something, they backported security fixes into the stable version like with every other package, it just didn’t have new features and improvements and the dev was sick of being asked by users to support the old versions.
Patching out the message (which was effectively PUP malware) on testing and then porting that to stable and shifting the default to LightDM and LightLocker in future releases seems like a good solution. I probably would have dropped xscreensaver altogether in future versions (which is what the author suggested) for being malicious, but at the time there weren’t a lot of reliable alternatives and it was better for users to still have the option.