Because Google owns both the browser and the search engine, and could use position in one market to gain a large advantage in another. Opera is neither a market leader nor it owns DDG. Moreover there is no such thing as anti-trust behavior, anti-trust is a legislation/action( the anti in its name ) that is aimed to stop such behaviour.

To abuse monopoly power you must first have monopoly power to abuse. Opera has no monopoly on desktop browsers.

Really? Downvoting me for asking a question in possibly the most polite and non-ignorant manner?

I know this is hacker-news, but do you guys really have to get into this anti-big company behavior?

dangrossman has given an adequate explanation though I have a question? Why couldn't the Opera people make it the default search engine? It's their piece of software and you're free to change it to anything you want.

People seem so quick to cry wolf.

From what I understand, most of their revenue for the desktop browser comes from the fact that google is the default search engine.

It's included in the list, not as default search provider.

That's probably their way of cat-playing with their food.

Also, they probably remember how microsoft was forced to carry a load of different browsers in EU and make WMP-free windows, so they take some steps to prevent that for themselves.

Also they used to disable this selector on per-country basis.