Feels to me like that is addressed by the very first sentence in the article:

> We influence others every day, whether we intend to or not.

And then it’s expanded as it continues.

> Every effective communication is manipulation to a degree.

Yes, to a degree. Seems to me the author is attempting to be pragmatic and not let excessive pedantry cloud the larger point. A friend trying to convince you to stop smoking because they want you to live healthier for longer may be technically manipulating you, but that’s not a useful definition and realistically no one would colloquially consider it to be the case. Whenever you find yourself dismissing an argument because a word can be applied universally, instead steelman the author’s argument by trying to understand the definition they are working with.