Better title: "Why I should have written ZeroMQ in C++, not C++ without exceptions."
Return codes in C are easily ignored even if they're serious. In C++ you are compelled to deal with error conditions even if your action is to ignore them. This is a fundamental philosophical difference.
Better title: "Why I should've learned C++ thoroughly before writing ZeroMQ".
There was some bitching about allocators, for example, as if he didn't know about the C++ allocator override feature which isn't even hard to implement. Then there was more confusion about template objects for things like `vector` where he was using them as you might a C linked list library, then complaining that you had to allocate twice as many objects.
I think the author is dimly aware of what C++ really is, and just refuses to play along because they'd rather be writing C code anyway.
John Carmack could probably tear apart every single one of those complaints in ten minutes and have time left over to talk about his new CTO position. That's because Carmack spends the time to learn his tools inside and out and doesn't simply bitch about things being not to his liking.
C++ is a broad church, and there is room for all sorts!
For instance, do you prefer cheap copies? References? Reference counted pointers with auto-destructors? There's many ways of doing it, you're not necessarily forced to pick any particular one, but not making use of these facilities and instead doing it C-style is making your life harder than it should be.
Between the Standard Library and Boost, there's a lot to pick from. There's no reason to go and roll your own vector just because you don't like or understand the way the standard one works.