I'm always cautious with my privacy but also at these kind of stories. I've also steered away from Chinese products (bar the Moto Z2 Play I just bought) for that very reason. Not because I'm convinced that they're a threat but knowing how their government works, I'd rather play it safe.
That being said, with all due respect to these 6 people, they're not putting forward any fact. They're only saying that people should be careful, which is true for all electronic devices that hold personal information and connect to the internet. Being in their position, of course they have a bias against China given the US' history with the Chinese government.
Truth be told, every device is a risk whether it's a mobile phone, a tablet or a computer. These people are just afraid that the Chinese government uses those devices for large scale espionnage. But unless they have proof to back that up, I don't think this should be any more of a concern to anyone that wasn't worried before. Just be careful what brands you buy, check your device with a trustworthy tool, if any and enjoy it.