jamesh,
Why? Do you simply only use software where sourcecode is available as a matter on principle, or do you actually look at the source code for some reason?
I can't answer for Thaddy but...
In cases like this we are being asked to download and install executables from somebody we have never heard of, that we can have no trust in and are hosted on a click bait website. Without the source we have no idea what malware lies within.
Isn't this something the security conscious computer literates have been warning us not to do for decades now?
Whilst there can be a matter of principle in preferring open source solutions there are very practical matters of security. Not to mention maintainability, longevity, etc, but that is another story.
Where is the incentive to invest time and effort beta testing closed source software?