Geez, I believe the issue is is that some items that are supposed to be waterproof and tough (leather jackets, hunting jackets, military uniforms) get soaked/drenched really QUICKLY, leading to cold, and leading to death.
The raincoat and gorka jackets are OP compared to anything else because they can tank rain eternally, and anything else won't even come near to these two in terms of waterproofness.
Also, small nonvital items get wet really quickly contributing to overall wetness - gloves, military boots, face masks, hats...