One of the major aims of the Codidact project has always been to create a community-driven knowledge-sharing platform. Part of that is the ability to collaborate: posts are not intended to just solve one person's problem or answer one person's question, but to provide solutions for people who come looking in the future. One of the ways we help provide for that is by allowing for community editing.
Not _everyone_ can edit directly: new users start with the ability to "suggest" edits, which are reviewed by more experienced community members. (There are also globally-editable post types which can be edited directly by anyone, but those aren't in use everywhere.) Once someone gains enough experience and a proven track record of good edits, they are trusted with the ability to edit directly.
Edits are encouraged to improve the post but not to alter its substance or meaning. That means that edits which fix spelling, grammar, etc are encouraged, as are edits that help provide clarification where a post needs it. Edits that change the meaning of the post or that add entirely new content to it should probably be an answer of their own instead, and you're welcome to point this out to editors and/or undo edits that do this - but edits that are an objective improvement to the post are the expected norm here.