Today's Logical Fallacy is... Essentializing!

This fallacy proposes a person or thing “is what it is and that’s all that it is" and, at its core, will always be what it is right now. This is related to the fallacious argument that something is a certain way "by nature" or based on its origin (genetic fallacy). This is a fallacy because it uses existing negative perceptions and stereotypes to make someone's argument look bad without actually addressing the argument's merit.

Examples: 

All ex-cons are criminals and will still be criminals even if they live to be 100.

Americans are cold and greedy by nature.

Women are better cooks than men.

Once a cheat, always a cheat.

Anyone who supports the legalization of marijuana just wants to justify their habits.

All blondes are dumb.