Kevin already said medkits not treating infection is a bug, so that’s a moot point when talking about coders intentionally sabotaging fun.
Additionally, the nerf to the knife spear was somewhat warranted since it was stronger than any other early game weapon by a huge margin given its range, speed, and damage. Plus it could be crafted within the first five minutes with no skill out of literal garbage. It made crafting any other weapon pointless until you got forging set up. This basically compounded to create a massive difficulty jump later in the game when the knife spear stopped being the end all be all to combat.
TLDR knife spear borked the actual difficulty curve because it meant players only learned to fight with it and were unable to cope with later game difficulty and enemies that couldn’t be kited.