As someone who loves Ruby dearly, there are a number of severe flaws that are hampering Ruby now.
The thing is they are hampering Ruby now because people want to use Ruby for all kinds of things he probably never intended it for.
E.g. I'm on a crazy multi-year journey towards doing an ahead of time compiler for Ruby. Ruby is not designed for that. It has dozens of issues that makes it incredibly hard to do that efficiently compared to many other languages.
At the same time, MRI was incredibly inefficient in earlier incarnations because it was simple. It interpreted the syntax tree. Easy implement. A nightmare to make fast.
Ruby's grammar is also a massive pain for people who want to implement Ruby. Great for developers mostly until you run into some of the hairy corner cases that are often a result of trying to be incredibly clever to make things flow very naturally when writing Ruby most of the time, which has led to a lot of byzantine rules.
I wouldn't give Matz flak over it, simply because some of it are part of what makes Ruby so pleasant to use, and others are simply artefacts of him meeting his needs while implementing Ruby rather than designing it to meet some ideal that wasn't necessarily very relevant to him then.
But I'm not surprised (a bit sad, but not surprised) if someone makes it personal.