BLUF.....

US tech companies "actively didn't care/want to know" about Russian propaganda or disinformation until 2016 election meddling AND still do not really care as many simply forget they are driven by advertising income and the number of views are what drives them......even if those views are based on fake news, propaganda, disinformation.....via trolling and automated bot nets.....the more the "views" the more the advertising revenue....

AND secondly, in the case of Twitter the largest single shareholder is a Saudi and the largest single investor is a Russian oligarch....at 1.3B USDs....