Someone who has an offering (idea, product, belief...) and wants to put it out for the grabs is getting involved in marketing. It is an open invitation to be part of the offering. They can have a simple process or a series of complicated ones, which include email list communicating, delivering and exchange. The understanding of this simple definition does not mean that some corporations do not indulge into unethical activities; it simply reminds us that not all those who are involved in marketing are aiming to deceive the public.
Let us take bread as an example. A bakery providing us with fresh bread is likely able to sell more of its fresh bread compared to two days old bread coming from a distant baker if it offers it at the same price. Both are involved in marketing if they want their product sold. They have the product, they defined its price, their products are available at the local grocery stores, and they both informed people of their presence (knowing that the local bakery can focus on its products' freshness).
How can either of those entities be criticized for their involvement in basic marketing? Let's take the example a step further. The Distant bakery is really looking into establishing a major market share in the market. Due to its transportation costs it cannot compete on price.