I dunno if it's true of all of the things but I found a beanie and a flag during the course of my first play through.
I don't see how charging for these items diminishes the quality of the game at all. If they were things that confured an in-game benefit or alternate levels, then I could see being choked about it but as these are little more than simple cosmetic changes I really don't see this as being a valid critisim of the game. There not being any advanced chambers, the length, those I can see people being upset about. Having hats and skins that no one is forcing you to buy nor there not being any disadvantage for not having? Seems like bitching to bitch.
I also don't see this as valve changing thier stance on DLC either. As far as I'm aware they still give away all of the playable or level dlc that they have made like the new campaigns for lfd. If they want to charge people for hats and shit to cover the cost of that, and if peple are willing to buy these things, which they obviously are, then I say let them.