Are you sure that you have the correct rights? Have a look at the demo that is running 3.17.3 as well and you can delete users there. So it is either a problem with your installation or with your user rights.
[edit] Just saw the bug report now and that this only happens when you are not the super admin. So I am not sure if this is a bug or a feature.
However, if you feel this is a bug, create a new bug report. Because the one you are referencing is for a completely different branch of Limesurvey.
Help us to help you!
Provide your LS version and where it is installed (own server, uni/employer, SaaS hosting, etc.).
Always provide a LSS file (not LSQ or LSG).
Note: I answer at this forum in my spare time, I'm not a LimeSurvey GmbH employee.
By the way, I don't think you want to post emails of members of the Central Bank of Costa Rica publicly, so I have deleted your screenshot. If you want to upload it again, please make sure that no one can see the email addresses.
Help us to help you!
Provide your LS version and where it is installed (own server, uni/employer, SaaS hosting, etc.).
Always provide a LSS file (not LSQ or LSG).
Note: I answer at this forum in my spare time, I'm not a LimeSurvey GmbH employee.