Google search engine/ads

I use chrome and Google's search engine, but I have an ad blocker installed so I never see their ads (that includes all the YouTube ads others see prior to a video starting).

Can someone explain to me how the EU says it's illegal that Google gives preference to its own products/services in ads over competitors? I mean it's Google's search engine so I would think it's understood they would try to get anything they do higher up: EU slaps Google with record $2.7 billion fine - Jun. 27, 2017

That's like saying a store owner can't place its own branded products near the entrance for more people notice with competitors' products in the back corner. Do they think search engines are some kind of public property?

Btw, the ad blocker extension I use in chrome is uBlock.