jaclaz sometimes makes typos, particularly on forum posts which are not exactly literature, I am correcting the original post, so that anyone else doesn't make conclusions on Italian grammar rules from a single post.
Your quoted statement should be read as "I noticed how ONCE jaclaz put a space before a comma"[1].
No space is required, nor intended in Italian grammar, the French are the only ones with that rule, I believe, Portuguese used to have "half spaces" until the 1920's or so, then they removed them.
jaclaz
[1] BTW that whole sentence has a second comma, and there was no space before that second comma, you could conclude that jaclaz is not very good at punctuation