Look, I understand typing quirks are a way of expressing yourself, but there comes a point where they just get in the way. Many typing quirks can make comments incredibly hard for people to understand or read as-is/with a screenreader. And, after a certain point, they can make comments outright impossible to translate into other languages. These issues can also potentially hurt moderation in the case that a comment should be reportedYou can always report a comment if you think it violates the Community Guidelines in some way. But reporting for style issues doesn't seem like it would work. Some “quirks” may actually be caused by a brain or physical disorder. Or somebody trying to use a language with which they may not be familiar. Or somebody trying to bond with a group that uses a particular style.
With these problems in mind, I think Scratch could at least include a report option for comments being too hard to read
If you are having difficulty understanding what someone is saying - politely tell them so. It's up to them to decide if it's something that can be improved - or not.