I own several books, movie tapes and music cassettes. I do not own the copyright of any of them.
No matter what the rightful copyright owners of those materials wish they can't delete my copies since I've acquired those copies legally. Surely you also would feel uncomfortable if copyright holders could delete your books.
SE has also acquired your content legally since you have agreed to the Terms of Service.
You agree that any and all content, including without limitation any
and all text, graphics, logos, tools, photographs, images,
illustrations, software or source code, audio and video, animations,
and product feedback (collectively, “Content”) that you provide to the
public Network (collectively, “Subscriber Content”), is perpetually
and irrevocably licensed to Stack Overflow on a worldwide,
royalty-free, non-exclusive basis pursuant to Creative Commons
licensing terms (CC-BY-SA), and you grant Stack Overflow the perpetual
and irrevocable right and license to access, use, process, copy,
distribute, export, display and to commercially exploit such
Subscriber Content, even if such Subscriber Content has been
contributed and subsequently removed by you as reasonably necessary
to, for example (without limitation).
- Provide, maintain, and update the public Network
- Process lawful requests from law enforcement agencies and government agencies
- Prevent and address security incidents and data security features, support features, and to provide technical assistance as it may be required
- Aggregate data to provide product optimization
This means that you cannot revoke permission for Stack Overflow to
publish, distribute, store and use such content and to allow others to
have derivative rights to publish, distribute, store and use such
content. The CC-BY-SA Creative Commons license terms are explained in
further detail by Creative Commons, but you should be aware that all
Public Content you contribute is available for public copy and
redistribution, and all such Public Content must have appropriate
As stated above, by agreeing to these Public Network Terms you also
agree to be bound by the terms and conditions of the Acceptable Use
Policy incorporated herein, and hereby acknowledge and agree that any
and all Public Content you provide to the public Network is governed
by the Acceptable Use Policy.
SE only loses the rights conferred by that agreement if the agreement becomes invalid. Like in the case of a violation of the agreement by SE.