Why its not int64, int32, unsigned_int32, vec, function for all language, but inventors have to change these to u64, i64, fn...etc?
Languages have many competing goals. It shouldn't take long to get used to u64 over, e.g., unsigned_int64, and brevity is valuable in its own right. Too many wasted characters can obscure the flow of a program and make it slower to read and understand.
Is it the right choice? I could be persuaded either way. I know it's one I've personally made before, choosing rebindings like i256 and cmpeq8 when doing a lot of bit-twiddly vector code.
Having said that, less typing and clutter are also beneficial, so it's really a net natural debate.
Personally I prefer it, mostly for subjective reasons but I think it makes sense - in the case of Rust it was the easiest syntactic novelty to get used to, things like lifetime annotations are a different beast.
When people do something differently than most other popular implementation it's good to ask if that's worth it.
"i32" and "u32" are used because they are short (and used often). They are just typedef away in C and are used ~forever, did you look at Linux kernel for example?
But I'm with you on the general sentiment - beyond trivial, lexical things like type names (which almost any language allows you to redefine anyway), Zig appears to have strong NIH mentality in regard to the syntax. Trying to replace C, but go out of their way trying to invent syntax just to be different from it and most other things too.
And a lot of people appear to notice and pay attention to this, as the discussion here shows.
Jumping thru hoops is what Zig seems to choose with its unorthodox, different-just-to-be-different syntax. I wonder, how many will want to jump with it?
Did zig run over your dog or something? You seem to be particularly hostile in your comments about it. As someone who has participated in discussions about zig syntax for years, I can assure you that a significant amount of thought and consideration goes into these choices. It is not "different-just-to-be-different". In fact, the very syntax being complained about is derived from other languages!