"Tech giants" mean very large tech companies, basically these: Facebook, Google, Microsoft, Amazon, Apple. This term is found often in the media, and is quite unambiguous.
Examples of rhetoric from those companies where they do the opposite of what they say: they often claim "you [the user] are in control". For instance
1. https://privacy.google.com/# ("put you in control")
2. https://www.facebook.com/facebook/info ("make the world more open and connected")
While it's debatable what "in control" is and what "open and connected" means, they make a bold claim without revealing the subtlety of the topic.
Not being honest about user data collection in NSA PRISMA is not exactly putting the user in control.
Google has a track record of deprecating services that were used by a sizable user base, such as Google Reader or Picasa. Shutting these down without even giving them out as open source or providing some migration path is not really letting the users be in control.
Google's core strategy is shifting towards suggestions, away from search. Page and Brin said this. https://www.youtube.com/watch?v=GpjOZGxKhRM&feature=youtu.be
While it could be argued that suggestions just create assistance like a personal secretary does, Google doesn't just assist on demand, it proactively suggests (and will do more of this, according to Page and Brin), and also shapes users' perception of reality (through Google Search results, which is the topic of the fine). So an entity has pervasive information about a person, does proactive suggestions and shapes their perception of reality is not exactly what I would call a mere assistant. I would compare that role to parenthood, which is consistent with Google's strategies: to know more about you than you know yourself, and to take care of you (which is aligned with their "Don't be evil" / "Do the right thing" motto. It seems they genuinely believe they are benevolent). That is, arguably, Google in control.
Now onto example 2, Facebook has long said it makes the world more open and connected. The mere fact that Facebook holds massive amounts of relevant content locked up behind a login wall means content is not accessible to search engines. This is the exact opposite of an "open" scenario. It's also debatable what they mean by "connected". It sounds like "people connected to each other", but in practice it is "people connected to Facebook", and incidentally also connected to each other. If their goal was to connect people to each other, they would pursue P2P, mesh networks (e.g. https://www.scuttlebutt.nz/ is one implementation), etc that allow local communities to connect with each other and with the external world despite the lack of internet infrastructure. In practice, their internet.org program is widely known to have dropped net neutrality when it was implemented in India and other countries, favoring Facebook's walled garden. This is the opposite of open and connected (e.g. it eliminates interaction with other people on different social networks like forums, Reddit, etc). They have plans to provide internet to regions that lack internet infrastructure through drones and satellites (http://www.computerworld.com/article/2855979/why-google-and-...) but the priority here seems to be getting those people connected to Facebook first, and then connected to other people. Cheaper and quicker solutions could be implemented simply with phones and P2P, allowing people to connect to each other first, and share data in a gossip style which is also scalable.
So there you go, two examples at least. It should be enough to confirm that I am contributing to the conversation, and I'd appreciate if no ad hominen comments are made, they just distract.