The idea here isn't that a company is evil because it's striving to make money; it's that they're deliberately doing less than their best as an economic tactic.
Whether true or not, there's something of an ideal people have about businesses in the marketplace. This ideal is that companies that focus on doing the best that they can in providing a product/service will rise to success, and the money will follow as a natural consequence - in other words, that cream rises to the top.
When people seem to start getting upset is when they see companies deviating from that model, and embracing a different one. This alternate model eschews excellence, instead believing that greater money can be made by providing a flawed/incomplete product or service, because then this virtually guarantees sales of future goods in the name of "fixing" or "completing" the initial item. It's what people have been accusing Microsoft of for years - that they provide an OS that looks nice and performs well...or would if it wasn't bug-riddled and flawed, requiring that you purchase the next OS to get a cleaner, more stable version.
Whether true or not, this is how WotC looks to a lot of people right now. There's a strong impression that WotC didn't create the best game they could have with 4E - or rather, that things many people consider to be near-vital were deliberately held back from the Core Rulebooks to boost sales of later splatbooks. After all, we were told outright that several classic monsters wouldn't be in the MM simply so that they could be included in the MM2 to drive up sales. People simply feel that WotC is less concerned with releasing a great game, than they are concerned with releasing a flawed and incomplete game to better guarantee sales.
To summarize, people get upset when companies embrace the idea of non-excellence as a viable marketing tactic.