This was actually intentional in an attempt to fix this some years ago:
https://www.vaultwiki.org/issues/2761/
However, I agree that CSS breaking is a better solution, since it breaks at the actual end of the line, rather than an arbitrary position, and doesn't add more spaces for words that have lots of HTML entities (like your screenshot).
This should be fixed in the next release.
However, please note that in most editor-entered content, there's not much we can do about extra spaces, since that would be based on your word-wrap settings in the AdminCP (which may be higher than 0).