The people who implement things like this do have their hearts in the right place. However, generally speaking, people are stupid. They will click through any message, no matter how strongly worded, in order to have a chance to see the latest, hottest celebrity du jour naked or to have a chance at scoring music or software for free.
Wording the message stronger or making the process to get to the "I accept the risks. Download anyway." option more difficult to coerce the user into reading the warning only results in the users moving to browsers that are easier to use to download stuff.
The only real solution, which isn't really a solution, would be to bundle a full-blown malware/AV into the browser so only genuine threats were flagged, but who in the world would want to tackle that coding job, ongoing maintenance, *and* listening to critics declare your browser as bloatware?
I'd love to see a browser with a dialog that had two buttons. One displayed a thumbs up to download. The other displayed a thumbs down to cancel. The dialog would simply read "Idiots gonna be idiots. YOLO"
Now I want someone to code a Firefox/Pale Moon extension that does that.