Why We demote URL through Webmaster?

[Joylinford]

My question is Why We use demote to block URLs in Webmaster?

[AvniShergill]

Basically, the sitelinks are generated by search engines which may not be always perfect. If you really don’t want to show inappropriate or incorrect URL, in certain sitelinks then you can demote the links from Google SERP by using your Google webmaster account.

[learn2do]

Basically, the sitelinks are generated by search engines which may not be always perfect. If you really don’t want to show inappropriate or incorrect URL, in certain sitelinks then you can demote the links from Google SERP by using your Google webmaster account.
Can't be more agree with you. A good answer!

[fayeseom]

If you think that a sitelink URL is inappropriate or incorrect, you can demote it. Demoting a URL for a sitelink tells Google that you don't consider this URL a good sitelink candidate for a specific page on your site. Google doesn't guarantee that demoted URLs will never appear as a sitelink, but we do consider a demotion a strong hint that we'll try to honor when generating sitelinks.

[rashikasaxena]

If the sitelink URL is inappropriate then you demote the URL by demoting the URL for a sitelink will show google that this URL consider a good site link on your site.