Why are there so many people trying to sell me into "Organic Upvotes"?

I have launched three products here on product hunt and each time I launch a product, the number of people reaching out to me selling me upvotes grows. I don't understand existence of such services. Is there no filter of sorts to prevent people from buying their way here? Also I have always seen this as platform to showcase the cool stuff you are building, nowadays its turning more into a rat race for a badge. Let a man get his honest upvotes, Thanks.