"there is no way to insert less than one row"

The following documentation comment has been logged on the website:

Page: https://www.postgresql.org/docs/13/dml-insert.html
Description:

The documentation here says the following: "Of course you can also insert
more than one row, but there is no way to insert less than one row."
I tried this in psql:
---cut---
mydb=> create temporary table t1 (i1 int, v2 varchar(100));
CREATE TABLE
mydb=> create temporary table t2 (i1 int, v2 varchar(100));
CREATE TABLE
mydb=> insert into t2 select * from t1;
INSERT 0 0
mydb=> 
---cut---
So, the last insert command inserted zero rows. What is meant by "there is
no way to insert less than one row"?