This is not a new issue but it is far from being generally the case that Fiverr members sell these encoded articles. Some do, they are a rip off. Also, we should remember that some buyers actually w
ant these encoded articles.
I always check reviews for providers. If there is a problem it shows up here.
Of course, an encoded article is not exactly hard to spot.

If you are provided content as an HTML page then you are being ripped off.
Only ever accept content delivered as a .txt or a Word document - I prefer .txt files, quicker easier and more 'Internet compatible'.
By the way, this is what 'encoded text' looks like:
Most people view the car-buying experience as a necessary evil in life. Buying a new car is exciting, but it can also be a stressful experience. Continue reading to find helpful tips to make the process smoother and easier.
The same code as seen in your browser:
Most people view the car-buying experience as a necessary evil in life. Buying a new car is exciting, but it can also be a stressful experience. Continue reading to find helpful tips to make the process smoother and easier.
I don't quite know how people can actually get misled by these tricksters.

If you do manage to buy this type of content from Fiverr providers without noticing then make sure to inform Fiverr, they have a vested interest in keeping their marketplace clean.
Of course this is not just a Fiverr thing. Pretty much any marketplace where buyers deal directly with sellers is open to abuse by both parties.