Oxford comma recommendation not relevant

[dariavladykina]

I am getting this instruction to use the serial (Oxford) comma in sentences like below:

In such cases, choose between linking to these sites or including their content in edited form.

In some cases, product managers will request avoiding all or selected external links to avoid issues for customers impacted by restrictive firewall rules.

Not sure why Vale suggests this because there is no reason for a comma in both.
File: xml/docu_styleguide.structure.xml