It's about choice. If people want to buy kosher, they pay more. This would be called a "value added" service.
No different (economically speaking) than any other "value added" service to a product: celebrity endorsement, attractive packaging, advertising. The list goes on.
You do not seem to want to answer the question of what is forcing you to buy kosher; because if you are not being forced, then this is your choice, and you have nothing to complain about.
If some people want to pay more* for someone else to say the product is kosher, who are we to stop them, complain or even question?
If I wanted to pay for my produce to be picked only by left handed midgets, that's my business - if I choose to make it available (at a higher price) to other fruit eaters, what's the problem?
Really dude (or dudette)- this is a non-issue.
*but it's not always more - as Karrie and I have written, sometimes the kosher product is cheaper.