You're getting way to worked up over variable types.
Back before CPUs and OSes were 64, or 32 bit, there were 16 bit CPUs and OSes. If your target system was 16 bit you might change the way things are declared.
uint16 and uint32 are most likely artifacts from the transition from win16 to win32.
You mostly answered this yourself. Different platforms, and different compilers treat types slightly diffrently. One environment might treat an int as 16 bit, another might allocate 32. Although, most environments today are 32 bit.
If you declare a variable with a meaningful name to match its size, there will be little doubt about it when you need to use it.
Programmers can define what ever variable types they want to. Just because you don't understand their code, or their motivation, does not mean that their actions, and variable types, are silly.
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How is a forum signature with xbox specs in it anything like drinking and driving?
Sure, a signature is a little boastful, but it lets others know that you know a little about modding. It's friendly competition, too. There's nothing wrong with that, is there? If you choose not to do it, or don't like it, that doesn't mean its stupid. More importantly, it has no comparison to drinking and driving.