Could Hostess sell something healthier than Twinkies? Yup. Could Harlequin publish something better than mindless drivel? Yup.
Should they? Not for me to say. Moreover, this line of reasoning inevitably leads to questions as to where to draw the proverbial line. Suppose Hostess gave up Twinkies and went into the fresh produce business. The fault-finding wouldn’t cease. (“They should import asparagus only from countries that treat their llamas better.”) Same thing if Harlequin switched to publishing classics. (“How dare they publish Crime and Punishment? The central character is a cold-blooded killer who questions the existence of God.”)
Instead of blaming marketers for what they sell, perhaps it’s time to accept responsibility for what we consume. No one, not even the alleged but non-existent powers of so-called subliminal advertising, can force you to buy against your will.
So if you object to a product, here's a revolutionary idea: don’t buy it. Nor must you buy your kids every toy they see on TV. Even if they can't tell a commercial from programming, I know of no law of physics preventing you from teaching your kids that nagging is impolite and that not getting everything they want is part of life.
Should some products be banned? Sure. Trouble is, that's a can of worms. What I would cheerfully disallow (acupuncture, chiropractic and assault weapons, for starters), others would vehemently defend. And vice versa.
Meanwhile, what is legal to buy should be legal to market. The two kind of go together.
As a side note, if you’re a marketer who objects to a product, I suggest declining helping to sell it. That is, provided you have that luxury. I have it, and I exercise it. Products of would-be clients I have declined include software purporting to predict stock prices (impossible), a multi-level company (generally a fraudulent system but for a few notable exceptions), an alternative “medicine” company (quackery, and downright dangerous at that), and a right-wing political organization bordering on fascism (let’s just say they’d have made the KKK proud).