There are only 846 administrators on the English Wikipedia. This is across 7 million articles, 118,000 active registered users, about two edits per second, about a million files just on Wikipedia (most of them are hosted on Wikipedia’s sister project, Wikimedia Commons), and over 60 million total pages (articles, talk pages, user pages, redirects, help pages, templates, etc.). So although they have this data, it’s not useful if somebody doesn’t notice and investigate it. Administrators are stretched thin with administrative functions, and that’s not even accounting for many of them participating as normal editors too (tangent: besides obvious violations of policies, administrators have no more say over Wikipedia’s content than any other editor).
Contrary to the idea that new editors sometimes get of Wikipedia as a suffocating police state run by the administrators, usually when edits get reverted it’s because regular editors notice this and revert it citing policies or guidelines without any administrator involvement (every editor has this power). If an administrator intervenes, it’s usually because a non-admin noticed and reported (what they perceive as) bad behavior to an admin, two editors are locked in a stalemate, or there’s some routine clerical issue to be resolved.
Sockpuppeting, copyright violations, etc. are often (even usually) found by regular editors who notice something amiss and decide to dig a bit deeper. Even with automated tools that will flag an edit that replaces the article with the n-word 500 times in a row, and even given that some non-admin editors have tools which let them detect some issues, there’s just only so much that 850-ish people can find on a website that massive. For example, one time a few years back, I just randomly stumbled across an editor who was changing articles about obscure historic battles between India and Pakistan to have wildly pro-Pakistan slants – where treacherous India was the aggressor, but brilliant, strong, and courageous Pakistan stood their ground and sent pathetic India home crying with shit in their diapers. The bias was oozing from the page (with poor, if any, citations to match), and I can imagine this would fly under the radar for a while on a handful of articles that collectively get maybe 30 pageviews a day.
There are only 846 administrators on the English Wikipedia. This is across 7 million articles, 118,000 active registered users, about two edits per second, about a million files just on Wikipedia (most of them are hosted on Wikipedia’s sister project, Wikimedia Commons), and over 60 million total pages (articles, talk pages, user pages, redirects, help pages, templates, etc.). So although they have this data, it’s not useful if somebody doesn’t notice and investigate it. Administrators are stretched thin with administrative functions, and that’s not even accounting for many of them participating as normal editors too (tangent: besides obvious violations of policies, administrators have no more say over Wikipedia’s content than any other editor).
Contrary to the idea that new editors sometimes get of Wikipedia as a suffocating police state run by the administrators, usually when edits get reverted it’s because regular editors notice this and revert it citing policies or guidelines without any administrator involvement (every editor has this power). If an administrator intervenes, it’s usually because a non-admin noticed and reported (what they perceive as) bad behavior to an admin, two editors are locked in a stalemate, or there’s some routine clerical issue to be resolved.
Sockpuppeting, copyright violations, etc. are often (even usually) found by regular editors who notice something amiss and decide to dig a bit deeper. Even with automated tools that will flag an edit that replaces the article with the n-word 500 times in a row, and even given that some non-admin editors have tools which let them detect some issues, there’s just only so much that 850-ish people can find on a website that massive. For example, one time a few years back, I just randomly stumbled across an editor who was changing articles about obscure historic battles between India and Pakistan to have wildly pro-Pakistan slants – where treacherous India was the aggressor, but brilliant, strong, and courageous Pakistan stood their ground and sent pathetic India home crying with shit in their diapers. The bias was oozing from the page (with poor, if any, citations to match), and I can imagine this would fly under the radar for a while on a handful of articles that collectively get maybe 30 pageviews a day.
TL;DR: Too few admins.