Remove no longer necessary factory

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.2+
| Fixed tickets | -

The doc says you don't have to use the factory anymore since 2.2, yet does so itself a couple of paragraphs later.

The other occurrences of factory usages will be fixed by #2927 

The second commit applies to earlier verrsion as well, but if i'm not mistaken, these docs aren't maintained anymore?