Believe it or not, the laws don't say verbatim "Fabricating, purchasing, or misrepresenting customer experience is deceptive advertising...". I can't really believe that this is a real question and that I'm trying to explain this, either. The actual laws are more specific, and combined with how the courts interpret them, cover a lot of different situations and try to do so in a reasonable way.
If you actually want to understand why "an actor pretending to enjoy drinking Coca Cola" is okay while other kinds of endorsements are not, in the US at least, you could start with the FTC "Truth in Advertising" website, and "Advertising Endorsements" specifically, or other resources on that page.
If you actually want to understand why "an actor pretending to enjoy drinking Coca Cola" is okay while other kinds of endorsements are not, in the US at least, you could start with the FTC "Truth in Advertising" website, and "Advertising Endorsements" specifically, or other resources on that page.
https://www.ftc.gov/news-events/topics/truth-advertising
https://www.ftc.gov/news-events/topics/truth-advertising/adv...