Asking for forgiveness v. Asking for permission

To make edits on Wikipedia you don’t to seek anybody’s permission. You go the page, click edit, make the edits and save the page, you are done. Your edits are immediately reflected to all the people who might be visiting that page. Don’t people make bad edits, insert gibberish on Wikipedia intentionally? They do, check out the recent changes. But the thing is, it easier to fix bad edits than to make them. Gibberish text on Wikipedia go almost as quickly as it come. What (mostly) remains are the good edits.