Opera is not to blame for high memory usage.
It's the websites and number of tabs and pages open that count.

More than likely the user does not use Ublock origin which blocks a great deal of website junk.
There is also the unresolved problem that nowdays websites are alive; they are constantly loading the background.
That means when once a website has loaded the user should execute a keyboard shortcut to mimic hit the X in the address, to halt content or kill the website. Technically, Opera, I believe, is at fault in this department as I believe they have a responsibility to help the end user out and therefore to kill webpages once they are loaded or after X amount of seconds; this feature is absent in All browsers including Opera. But is such a vital feature.

Why does Opera open Explorer.exe TCP connections?

It's not I have attempted to browse for a file to upload to virustotal.com

I want to know why, and how to stop these connections.
Unlike Chrome which opens many Explorer.exe connections, Opera only opens 1 so I salute the dev team for that but still:
[Explorer.EXE]
TCP 192.168.0.14:1248 c3:https ESTABLISHED

I know opera is the source because the connection does not appear unless Opera is launched.
Now there is a chance that malware could detect the launch of a browser and thus to disguise its connection the moment of opportunity. However, as you can see the IP address is home and not on the interweb, and there is no process other than Opera which shows an interweb IP address. So it would have to escape netstat detection. For that reason, I pretty sure it's Opera which is creating the connection. From my stand point, I see no reason for an Explorer.exe connection unless the user uses the browse file feature on a website.

So I ask again, Why does Opera prematurely open an Explorer.exe tcp connection?