The closed nature of these companies feeds into this sort of thing, though. A frequent complaint of channel owners is that they aren't told why they've received strikes against their channels. Google also makes it incredibly difficult to submit feedback about their platforms. And any time something questionable or unfavorable arises, they just claim that it's the mysterious will of their overly-complicated algorithms that simply cannot be explained, despite being deliberately engineered by their teams of developers.
On top of that, there have been clear examples of censorship. For example, when Google specifically targeted Christian websites in a blacklist on Google Now [1], or when they were noted for scrubbing autocomplete results that were critical of Hillary Clinton around the 2016 election [2] when it was also revealed that then-Alphabet chairman Eric Schmidt had been a major supporter of Clinton for years [3]. These things seldom get questioned, and even then rarely get answers. It's hardly surprising to see why many people don't trust these companies and jump to conspiracy theories when these things happen.
[1] https://www.christiantoday.com/article/google-is-blacklistin...
[2] https://www.dailymail.co.uk/news/article-3636048/Google-accu...
[3] https://www.businessinsider.com/wikileaks-emails-google-eric...