You are agreeing with them.

They called it 'int' instead of 'int32_t' because it was meant to be the natural word size. It was supposed to float as the natural word size increased and allow code that worked on one word size to transparently work on the new word size.

Not floating to 64-bits on amd64 means their rationale for not giving it a fixed size was wrong. That is a simple width-doubling to another power of 2, the easiest possible case to expect to work transparently, on a compatible instruction set and they still chose to not float the size.

You can not just transparently change the word size and expect it to work, so you should just fix the size or use a fixed size. The notion of only having floating sizes as primitives was a mistake.