Because Nielsen, for instance, probably wouldn't slam this design as hard as you have: For a work in progress, it's pretty danged good. The homepage is obvious, it presents the most important things in a way that nobody could miss. I'll grant that the "binaries" link is a bit obscure, but that's copy. There's some wasted space on the homepage but that's not a huge deal because the website's simplicity puts most things only a click or two away. The "packages" page is great! The tutorial could use a monospace font, but otherwise is great too.
I really hope that your advice doesn't result in iolanguage.org becoming a clone of Rust's website or otherwise an impersonator. The authors here are trying something new and unique and what they've pulled off is already looking sharp and easy-to-use.
So yea, I think you're just trying to sound like an expert. Trust me, you're not the only person here who knows about usability (if you do, that is -- you come off as more of a frontend developer than a real UX person, because your suggestions are lacking in depth and experience, and the HTML/CSS bit in your reply makes you sound especially green).
It's easy to change the look and feel drastically with CSS, while keeping the file structure and HTML layout. It's not any different than downloading or using a website template, which is itself not much different from using a library in any programming language. Standing on the shoulders of giants is a core value of software.
> Why do you insist on dominating the thread like this anyway?
I only mostly replied to people who were in my own comment thread. That's called a conversation.
If I've inserted myself into anything unnecessarily, it's because usability and accessibility are really important to me. I want languages like this to succeed on their merits, rather than suffering due to unfriendly design. Plus I have friends and relatives with visual impairments.