"one language only" if you don't count the javascript, html and css.
My hunch is that you strove for making the First Comment considering that the point of this project is exactly what you said it isn't.
https://www.reahl.org/layout, for instance, talks about how styling works.
Taking this further, here's a comment from one of the maintainers on the relevant Google Group:
> Hello.
> We want casual users of Reahl to be shielded from complexities such as client side scripting and CSS.
> HOWEVER, if you are prepared to move to the next level of learning you can build your own Widgets. When you build your own Widget you can do anything you like - using techniques tutorial.pagerbootstraptutorial.pagerbootstrap that you would have used with a traditional framework.
Hopefully this answers your question.
I really don't think so. It might not be as mature as one might want in production, but from what I can tell, it certainly fulfills the title's assertion in enough useful contexts to be accurate.
But it may be close, like you can spend 90% of your development time on Python, and write JS components in the remaining 10%.
About half-way down is "Write code for a JavaScript widget"
You seem pretty steadfast in your commitment that this post misrepresents its content. I believe you should give it a deeper review and reevaluate your understanding.
What's wrong with simply "Reahl 4.0: Build web apps in Python".
It's clear and truthful.