I've encountered this pattern several times over my career. Some very smart programmer decides that for "reasons" the standard way to do something is "bad". (Usually "performance" or "bloat" are words bandied around.) They then happily architect a new system to replace the "old thing". Of course the new thing is completely undocumented (because genius programmers don't waste their time writing docs).
If you're _lucky_ the programmer then spends his whole career there maintaining the thing. If you're lucky the whole thing becomes obsolete and discarded before he retires. Hint: You're not lucky.
So what you are left with is this big ball of smoosh, with no documentation, that no-one can figure-out, much less understand. Oh he designed this before multi-core processors were a thing? Before we switched to a preemtive threaded OS? Well no, none of the code is thread-safe, and he's left the company so we need someone to "just update it".
There are reasons standard libraries exist. There are usually reasons they're a bit slower than hand-coding specific cases in assembler. There are reasons why they are "bloated" with support for lots of edge-cases. (like comments).
When some really smart person starts talking about how it's all rubbish, be afraid. Be very afraid.