It appears in places where that are neither personal websites nor blogs, and that are places where professionals conduct work.

For instance: The act of searching the Arch Linux wiki produces a picture of the anime girl.

(Should I just not use Arch professionally?)

If you care that much, you can donate money to Arch to buy a commercial license, or inform your sales rep that you find their conduct unprofessional.

Or, yes, you can take the presence of the free version as a sign that the professional service is freeloading, and take your business elsewhere.