Why create a second variable for the same value?

$uParams    = JComponentHelper::getParams('com_users');

+       // Check for admin activation. Don't allow non-super-admin to delete a super admin
+       $userParams = JComponentHelper::getParams('com_users');
+ 
+       if ($userParams->get('useractivation') != 2 && $user->get('id'))

we already have $uparams...

Confusion between model and controller... Thanks Jean-Marie for spotting it ;-)

PR updated!
Please test

Do NOT merge this.
See issue here:
#4376

@test
I can reproduce the issue on 2.5.28-dev, it is still there. But it has been fixed in 3.3.x but with different PRs, revert from regression. Please help me to find what code should be back ported from 3.3.x, if possible, to fix this in 2.5.x!

@infograf768 thanks for pointing the issue for NOT merging this (I am STILL learning joomla core code while contributing) but how to fix this now?

Well, persevering, after having read a lot on docs.joomla.org... The issue is still there, was initially reported on JoomlaCode. This was ONLY a PR to fix it, but PR code is no good. So I've open an new issue #4841 without PR, copying details from issue report. Thanks.