PSA: The monster list is NOT COMPLETE. These are just the confirmed monsters from a teaser. Capcom has said that Iceborne content will rival that of the base game, which means you're looking at 20 monsters at least with free DLC extra content.
Also, an EXPANSION is not a DLC. All Monster Hunter DLC was free for a year - festivals, monsters, more weapons and armor. There's plenty of content on original release. The expansion is, like any other game, a paid addition with a whole new zone, new mechanics, etc. This is a very fair business model and people shouldn't be upset for the sake of it.