This issue is independent of topic or side. Astroturfing is real. For instance you obviously don't just take Amazon reviews at face value. In the past doing such things in social media, including forums like this, was much more difficult because you need to generate an entire persona around an account to make it not an immediately obvious inorganic account.
And so the cost:reward there was relatively poor leaving it to things like militaries and governments to carry it out for influence campaigns and what not. But LLMs have now completely changed the game. You can easily create an arbitrarily large number of passably believable personas and backstories, autonomously, with no real limitations on scale.
This is obviously going to be abused when the stakes are sufficiently high. And in this case we're talking about a market that these companies likely believe to be worth trillions of dollars. And they can likely even convince themselves that what they're doing isn't immoral pretty easily, in the same way they convinced themselves that letting their software be used to kill people by the all-so-ethical US military is perfectly cool. So why in the world wouldn't they 'inform people of the strengths of their product' on a wide scale?