So originally I was unaware of this fact. But I was doing some reading on Arch Linux and found about this.
This story was from 2012 which really shocked me. My belief was that canonical started their shady practices around 2015-2016. Seems not 
But I highly recommend reading the short article. The comment section is very amusing
p.s. Oh wow, people were mass complaining about Gnome since then!
Not me, I'm okay with Gnome on most things, as long as Zorin OS can do their stuff to change layout and stuff.
Yup, exactly the time frame we ditched Ubuntu for Mint Linux. I still remember my disbelief when I saw Amazon listings among the desktop search results. 
You can still find Amazon preferred at the top of Software Channel.
On Zorin OS 12.4, I remember removing the Amazon Apps that came pre-installed.
I think part of why it rubs so wrongly, is it reminds us of Google Behavior.
That was around the time that Gnome switched from using resource files to using css. It upset a large number of people. But change is not always bad. Personally, I think that .css was a better way to go.
But just because a change is good, even under resistance, does not mean all change enacted is good, even if it is resisted.
Gnome came under new leadership - and changed its philosophy drastically. Rather than believing that they were a desktop for users, they began to believe that They Own The Desktop. We are just borrowers of it.
Possibly because you are able to see its pros rather than the cons. Whereas someone like me is blindsided by some of the severity of its cons. Neither is right or wrong in it. It comes down to not just preference, but how the software is used. What one relies on heavily, another may barely use.
I find that to be the great thing about Linux. What differentiates it from Windows is the availability of User Choice.
What disturbs me, greatly, is how much Gnome wishes to remove that choice. Not so much in design, as much as in over-all influence and behavior. Following the trend, it will not be long before Gnome takes action against Gnome-Extensions being available as they do not adhere to the Gnome Mission Statement.