I have wondered about this many, many times
Why do programmers miss the unreadability when text / fonts is light on a light background ?
This has been going on for a long time now and it should be obvious that it needs to be fixed.
Have a nice weekend 
as a professional designer this ticks me off no end.
It’s because it “looks cool” and designers are traditionally visual people. They read (well, used to) read zines with cool-looking stuff, and that is what they see as “good”.
But this is a tool, and functionality needs to come first.
Having something that looks beautiful while being intuitive and super easy to use is very, very hard.
The problem is that when it is done correctly, it looks simple! Like “well, of course, how else would you do it? What’s the big deal?” What you don’t see is the weeks of trial and error and tweaking and reviewing.
I was hoping that the WCAG and other such initiatives would have solved many of these issues, but unfortunately, they have not.
Also, as the designers already know what each of these informational blobs is, they don’t realize that to someone who DOESN’T know what those informational blobs are for, the interface is cluttered and confusing.
Being able to put ones brain into an “I have no idea what any of this is or what it’s for” state is not a skill that is taught in design or UX schools and one which is definitely lacking in modern software.
My mottot has always been: If you can’t read it, it sucks.
