The first link you gave,
http://www.imdb.com/user/ur23932597 is to a User Account Profile.
Anyone visiting IMDb, whether he/she is credited in film or TV or not, can create such an Account to create settings for viewing the site, chatting on message boards, creating lists, writing reviews or submitting data to the database to add or correct credits etc.
The second link,
http://www.imdb.com/name/nm4442828, is not to an "Account" but it's a Name Page, a part of the database of film credits, that is designed to show a name that has appeared in credits and list other credits and other data referring to that person.
I am a user,
bluesmanSF at
www.imdb.com/user/ur10114372. My User ID is not searchable in the database because "bluesmanSF" has never been credited in film/TV. There is no Name Page in my name or credits to list.
Glenn Ford at
www.imdb.com/name/nm0001229 is represented by a Name Page that is searchable by his name and lists his credits. But, he has no User ID because he is deceased.
You have both...a User Account you can log into via your email address and password and use features of the site.
You also are represented by a Name Page in your name which is searchable and will display credits and other data. Name Pages are owned and controlled only by staff and cannot be "logged in" to by users of the site.
A Name Page and User Account cannot/should not be merged or combined in any way because they are 'apples and oranges' with different purposes. You can delete a User Account, if you like, but you'd need it to submit requests to list credits, add a bio, etc., to Name or Title pages of the site. Name Pages with valid credits on them cannot be deleted. You'll probably wish to have both.
If you have IMDbPro, however, you or your representative can "claim" the Name Page in your name which creates a link between them allowing you to upload photos and add a resume page.
