I just updated to CC 2017. And I noticed that I have 2014 and 2015 versions on my computer of all the programs I use.
The default behavior of the CC 2017 installer is to remove old versions.
When you updated to CC 2017 did you specifically uncheck "Remove old versions" in the Advanced Options?
Ummmm. Nope. I didn't even notice that option.
Seems odd that old versions are still installed when the default is to remove them.
Almost all posts in these forums about CC 2017 installation and old versions are from people being surprised that old versions were unexpectedly removed which is the way Adobe has set the default installation behavior. Many people, me included, feel this is a mistake. Yours is the first post I've seen saying that old versions still exist.
Which operating system are you running?
OS 10.10.5. Why do you think that it's a mistake? i.e., what is the benefit of saving older versions? I'm afraid to remove them... but I know they are taking up lots of space, so I don't know if I need to keep them.
Lots of changes in CC 2017 compared to previous versions. Interface changes. Features removed or changed. That upsets established workflows for many people.
Plus not all previous version extensions and add-ons work in CC 2017 yet so many people want to keep using old versions... then find they've already been removed.
To answer your question about uninstalling, follow these steps: