Hello this is Philip the author of these reports and lead for the GCC Rust project. I feel its only fair to point out that the comment you link to the author is not a "main dev for gccrs".

I wrote part of the reasons for why I am working on gccrs here: https://news.ycombinator.com/item?id=28368924

Overall I feel sad that this effort has been perceived as some kind of attack against Rustc and its community by some. This effort of mine dates back to 2014 and then I was able to get quite alot of rust working in a short time but the language changed far too much to keep up as a solo effort. Since late 2018 I restarted the effort and seriously almost started the track to develop the a gcc backend using libgccjit, it is 100% something i have considered and thought through.

I will be giving a talk on this project at LPC if you wish to hear more about my reasons please listen then https://linuxplumbersconf.org/event/11/contributions/911/