A business’s viability outside of advertising doesn’t change the morality of advertising.
Regardless of which side of the camp you fall on, you can’t argue that ads are “good” just because some businesses need them to survive. In fact, I’d wager if a business NEEDS ads to survive, it’s probably a net negative on society as a whole.
That's when you call any type of promotion advertising, in that case, sure, there is some innocent advertising. People here are (obviously) talking about 'modern' advertising which is what google/fb etc are doing which is just plain bad for everyone except for Google shareholders (I would imagine, besides money, it's not even good for the people working on it as it must do your head in to be a brilliant engineer and then working on tech so miserable and foul as that).
Especially if it's an ecommerce business.