You say "like these" as though you know this is a "conspiracy theory". An amusing comment I heard recently "the difference between a conspiracy theory and news is about eight months".This is a great article by a friend of mine on the massive increase in conspiracy theories like these in recent years.
In the article your friend wrote, he begins with an example that can be, I believe, quite accurately called out as a conspiracy theory (pizzagate). From this, he seems to generalize to anything that gets labeled "conspiracy theory". He specifically says "without recourse to the content of the conspiracy theories themselves." The rest of the piece then goes on to argue about public good, which I felt didn't connect very well to the introduction and I came away without a clear sense of what his point was. In the introduction he makes reference to "A recent study in Psychological Medicine from researchers at Oxford" so it seems that maybe his point is something like we need more compliance with the governing bodies for the common good. I followed that link to see what they are calling conspiracy theories and found a chart that indicates that most people do not believe these things even a little. The one that sticks out is "Coronavirus is a bioweapon developed by China to destroy the West." where only about 50% of people disbelieve it. The way this one is phrased is worth comment. There are several elements here that could be true. It seems that it is possible that the virus leaked from a lab in China. It is possible it was being investigated for use as a bio-weapon, although there are other explanations like search for vaccines for viruses that do not exist yet. And it is certainly true that China wants to overtake the West as far as influence on the world stage. With all of these possibilities intertwined into that statement it seems likely people would agree with it even if they would not word it like that, giving a false sense of the level of agreement to a seemingly far fetched statement. (and I should note that far fetched does not necessarily mean false).
So what prevents one from grabbing one thing that could turn out to be true and throwing in a bunch of other things that are probably not true and then labeling the whole package as a conspiracy theory. You can tar the whole package without engaging with the main, possibly true, thing that is trying to be debated.
In your friends article he quotes
It seems to me that three scientists having an open discussion on a podcast falls into the category of relevant objections (the link I posted previously). Furthermore, removal and suppression of such dialog, as youtube is engaged in, falls into the category of too adversarial.such dialogue requires openness on our part to the widest range of relevant objections that can be advanced by them against whatever case it is that we are making. Such dialogue is therefore a cooperative form of enquiry, which fails insofar as it becomes too adversarial.
I am well aware of this, they call them conspiracy theories or hatespeech and do not want to delve into the details to find the truth of the matter. This is similar to your friend generalizing anything labeled a conspiracy theory as though it is false by virtue of the label while simultaneously refusing to look at the details of the claims.One thing you don't seem to know is that those on the left also blame media distortions for widespread opinions they disagree with.
I argue that we actually have to look at the claims and not trust the label of "conspiracy theory". And that we need to listen to a wide range of opinions specifically of people who disagree and hear what their points are. I agree that the main stream media and social media is doing a poor job but mainly because those who disagree are banned, suppressed, demonitiezed etc in an attempt to preserve the perceived popular agreement (ie maintaining the narrative). In the case of coronavirus this is ostensibly to generate greater compliance with government prevention measures. Which seems to be something along the lines of what your friend is arguing for.
In this regard, I do pay attention to people on the left. The Dark Horse podcast to which I linked is actually a fairly lefty guy and I quite enjoy his discussions. Joe Rogan is also a fairly lefty guy and frequently listen to his podcast (although not as much since he switched to spotify). The New Discourses podcast is also coming from a guy who is fairly lefty as well.