When Did it Become Okay to Try and Sell People Things on Facebook?

And I'm not talking about the Marketplace where people can scope out goods that other people are trying to sell. I'm talking about the full on sales pitch from someone you don't know on Facebook messenger. When did this become a thing?

Since I started in radio I have been getting friend requests from folks I don't know and I assume they are other people in "the biz" or listeners so most times I will accept. However, a few times these random friend-ings have resulted in a lengthy facebook message about that person's line of skin care products or body wraps (which I am not fully confident what those are)

Personally, it rubbed me the wrong way. I feel like it would be different if it were someone I know who happens to sell these products and wanted to give me the heads up they are selling (such and such product) and let them know if I wanted more information. But coming from someone I don't know it felt like they were using Facebook wrong. But maybe that's just me!

Have times changed? Is Facebook now an appropriate platform for people to sell their products?