It's a bummer, but unfortunately necessary sometimes.
As to WHY people do this? Well, for the same reason there are thousands of people using things like Amazon's "Mechanical Turk" to earn fractions of a cent for each time they choose an appropriate tag for a photo, or transcribe a supermarket receipt. Copy-pasta is seen by some as a quick way to earn 1/4c on something. They actually have ZERO interest in what you are saying or doing, they are just looking for the "quick and dirty" way to make 1/4c. But WHY? Well, 1/4c means nothing when you live in Australia or or the US, but if you live in Bangladesh or somewhere like that, those 1/4 cents become actual money fairly soon.
Sad, but true....
=^..^=
I understand that the economics of it works very differently in other economies, but even still, with the effort that goes into making these quick and dirty cents, you could be earning much much much more with interesting original content. It doesn't even have to be hugely interesting, just something about your day, or your life!