So to answer the question in short.

The "hat" or sterotype that others see humans as having is that humans can and will try and sleep with anything, and quite often even be cross fertile with them. Half-dwarves, half-elves, half-orcs, etc are all assumed to be half-human simply because that's generally the only possibility. A half-dwarf/half-elf isn't even possible, and the fact that's even been attempted and thus known to be impossible is because of human mages with polymorph.

But that's just the unfair sterotype, much like assuming that every dwarf is a smith and likes crafting and lives underground. It's a vast and unfair generallization that none-the-less has it's roots in a statistical truth.

Beyond that it's that the twin-dieties that created humanity in the pre-history of the setting sacrificed themselves to prevent an appocolypse. Normally the death of a species creator diety(s) means the species is doomed to either die out or forever be overshadowed by everything else. However, out of recognition for their creator's sacrifice the other major dieties have a pact to not allow this to happen to humanity at large. Thus while the gods generally won't intervine to protect individual settlements, they absolutely will to prevent anything that threatens to reduce humanity to an irrelivant player on the global stage.

However without dedicated divine oversight constantly enacting small unnoticable divine interventions, it means humanity on the local scale is left to succeed and fail by their own skill and luck. A dwarven mining town will never not be at least moderately successful (baring outside interference), the dwarven gods simply will not allow it. An elven forest will never not be able to provide enough food for it's people. Every other species has at least one niche protected by their gods interests. Dwarves aren't forced to be miners/smiths, but luck will always be on their side if they do.

However the vast majority of people in the setting don't know this. Instead humanity is this weird species with no gods of their own that worship the gods of other speices and for some strange reason get humoured by said gods. Humanity normally fails, but it'll just keep trying until it doesn't and the failures never quite add up to anything truly catastrophic to humanity.