"just last month I found MySQL, heck even SQLite supports triggers with code inlined into the trigger body but PostgreSQL mandates writing a separate function for the trigger"
The right response, as a postgres developer, is to agree that you describe a useful feature, and perhaps implement it to help other users.
But my advice to you is to be willing to put up with some short-term annoyances. Sometimes the best choices are a little annoying, and if you refuse to consider them, it will cost you (or your employer) much more later.
It is listed on the TODO https://wiki.postgresql.org/wiki/Todo page, apparently since 2012. I haven't coded in C since 1998, I do not think you want me to touch the PostgreSQL code base.
The right response, as a postgres developer, is to agree that you describe a useful feature, and perhaps implement it to help other users.
But my advice to you is to be willing to put up with some short-term annoyances. Sometimes the best choices are a little annoying, and if you refuse to consider them, it will cost you (or your employer) much more later.