Those people are angry because:
1. They are employed by, or they are a relative/friend/spouse of someone who is employed by, a manufacturer/distributor/retailer/installer of skimmer/filtration/waterchange/additive products. There are over 10,000 stores in the world that sell these products, with several people working at each one. That's a lot of people to post anti-scrubber comments online. And they are paid to do it.
2. They have a lot of money invested in their skimmer and other filtration equipment. So they feel ripped off to find that a cheaper piece of equipment can do a better job of removing nutrients. It makes them look unprepared.
3. They had aquariums in the 1980's, 1990's, or early 2000’s, when scrubbers were built and operated incorrectly. Scrubbers back then were noisy and caused yellowing and clouding. Scrubbers today don't. But these people have not used a modern (after August 2008) scrubber, so they think all scrubbers still operate the same.
4. They don't understand how scrubbers work, and they are not going to learn. They think that skimmers remove Ammonia, Nitrite, Inorganic Nitrate, Inorganic Phosphate (i.e., all the bad stuff). But skimmers don't do this. Not even a little. Scrubbers do.
5. Since they already have a setup that works properly, they have no reason to expend the time and energy to change. This is understandable.
