You can argue the necessity of those actions, but trying to call those actions examples of free expression is the kind of corporate double-speak that erodes trust.
What I see youtube doing is promoting content they like. The video is not itself deleted, its just not promoted (both to users and advertisers). Would you really call that suppression? You can argue its suppression in the sense that when you are so powerful any decision regarding disadvantaging someone is suppression. But I am not totally convinced by that argument, because curating a platform is their entire purpose at this point.
Then they made the algorithm changes. Instead of showing me videos I like, they suggest videos they like. Those videos often clash with my values or beliefs, but because they are mainstream, they get pushed anyway ad nauseum.
The change of state in the algorithm could be considered suppression. Another way of looking at it would be just the viewer counts of certain categories of videos has plummeted. Alt-right speakers and lecturers, flat-earthers, trump supporters, racial identitarians, and so on have seen a massive drop in viewers. Right or wrong, that algorithmic change that led to a drop in viewers is a form of suppression.
I want to emphasize that suppression isn't always wrong. A massive site like YouTube has to monitor for violent social contagion and contain that. But I don't think they should then use their suppression as an example of free expression, because it's not.
Edit: also to be absolutely clear here, the definition of "suppression" I'm using is the intentional attempt by YouTube to reduce the viewership and engagement in something.
when is it correct? Who makes that judgement?
People differ in their opinions. It's clear that some media should be suppressed, like violent calls to action by powerful people. It's clear that some media shouldn't be suppressed, like videos of puppies. In between lies a vast gray area where it's less clear.
> Who makes that judgement?
People do, particularly influential people who make judgements and have the capacity to illicit the change required. Currently it's set by corporations, but the bounds of that are heavily influenced by and can be superseded by governments. That's why after the 2016 elections, you had all the hearings of the owners and managers of big social media sites.
But not to assume malevolence ...
It's humorous how the aristocratic class is so much more Marie Antoinette these days.