FWIW Gardner is denying the claim that the Markup has changed its mission. And The Markup's various about pages have not changed (from what I can tell, when comparing to Internet Archive), including mentions of its investigative mission. For example:
https://themarkup.org/donations-faq.html#negative-tech-stori...
> Most of our stories will expose problems; that’s just the nature of investigative journalism. (As George Orwell reputedly once said, “journalism is printing what someone else does not want printed; everything else is public relations.”) But that doesn’t mean we’re anti-technology; we have the same love/hate relationship with technology that everybody does.
That said, this is a pretty specific claim:
> According to Angwin, Gardner, the former head of the Wikimedia Foundation, created a spreadsheet ranking candidates for reporter positions according to their views toward technology companies.