I don't understand why this is a problem for some people.
It doesn't increase the price or impact your buyer experience in any way, so why do you care? If this blog post introduced you to a product you wanted to buy, why should you have a problem with the author getting a finders fee from the seller? Just seems mean-spirited.
It impacts the buyer experience.
These two statements have a very different impact:
1. I love product X and I won't get paid if you buy it too.
2. I love product X and I will get paid if you buy it too.
Money motivates people to claim they love a product or that a product is good, even if not true. It's a problem that has plagued the internet for decades.