I view it more like the recommendation to wear a helmet on a motorcycle, or bicycle. It’s there for your safety, and the safety of other motorists & cyclists. Some areas could make it a law, if they wanted. The general sentiment is that “safety is better for humans”, because human communication as emitted through the teeny-tiny straw of 1, 2, and 3 character replies will lead to more discord, more disruption, more people getting angry at each other because they didn’t explain what they meant by that.
There’s precious little evidence of that in the last 6 months of posts, or the last few million posts in Discourse. And I favor data over opinions. Now if you were building a real time chat system, versus a system of discussion, you might make different design choices.
Honestly, if you view the new 4 character reply minimum as cramping your personal expressive style, I think you’ve got bigger to fry. Remember the default is twenty!