It also puzzles me as why people think hiring mod developers and releasing professional versions of the products is considered a bad thing.
It's not considered a bad thing in my mind, but when people give credit to the parent company instead, then that's a problem.
Sorry if I see this differently, but now I see Valve as a money leech preparing multiple small packages for purachse, rather than providing content for free such as companies like Epic. Of course, as a business practice this is about as fine as it gets. Business wise there is nothing wrong with trying to keep your company healthy, so I'm not saying Valve are wrong in this case.
I just happen to admire those companies that try to please a community with free content more than those that try to sell it. It somehow seems more "honest" to me.