You are taking this statement totally out of its context. The linked article discusses certain limitations and thresholds. Your quote is from the section about Content Database Limits.
This section "lists the recommended guidelines for content databases." It then follows with several entries for different content database size limits and column for Notes that describe which scenario is best suited for that database size.
In the row for "No explicit content database limit ", the notes then contains the opening statement:
Content databases with no explicit size limit for use in document
archive scenarios are supported when the following requirements are
met:
One of these requirements is that
Less than 5% of the content in the content database is accessed each
month on average, and less than 1% of content is modified or written
each month on average.
So, THAT is the context of that statement.
That statement does NOT apply in GENERAL for all sites created with the Document Center template.
It's pretty clear that this statement is a condition for a scenario.
Do you really need somebody to read and interpret stuff like that?