It’s in all probability as a result of Satoshi Nakamoto was typically reasonably careless.
It’s a deviation from established requirements that has no good cause.
Simply as interoperability amongst totally different Bitcoin node implementations is guided by Bitcoin Enchancment Proposals (BIPs), interoperability amongst computer systems on the web is guided by a system of Requests For Feedback (RFCs). It appears seemingly that the BIP course of was loosely modeled on the sooner RFC course of.
RFC1700 by Reynolds and Postel in 1994 says
When a multi-octet amount is transmitted essentially the most important octet is
transmitted first.
That’s to say that “Community Order” is big-endian.
Pc {hardware} (the CPU and many others) could be little-endian or big-endian. An software operating on a little-endian machine is anticipated to translate to and from big-endian when speaking over the Web. networking libraries present for this. Most community protocols and purposes do that.
Satashi Nakamoto failed to do that correctly.