This is pretty much a repeat of the tread switching hullaballoo.
You assign arbitrary definitions to whether something is "obvious" vs "not obvious" based on your narrow, anecdotal, and self-centered definitions of what these words mean.
Here's the real deal.
All these things have existed in various forms for far longer than DOTA 2 has been a game, and they could've been changed at any point in the game's history. These were things you learned because you saw someone else do it in a game, or something your gosu-pro friend taught you. You're, once again, missing my real point that this game is built upon these things you consider "bugs". The fact that you don't consider them bugs now is only because a long enough time has passed that these weird mechanic quirks have been grandfathered in, despite having no real basis, nor exposure through the UI, for a long, long time.
In 2006, there were players just like you who thought Battle Hunger being unpurgable was a bug. Play-dota even had a mechanics subforum dedicated to documenting and explaining all these "bugs", which eventually became just another part of the game.
In 2020, there will be someone exactly like you who thinks bottle refills are a trivial mechanical quirk anyone can figure out and some other esoteric but easily replicatable and accepted mechanical interaction that is a "bug" and should be removed.
The mechanics weren't programmed to conform to the tooltips. The tooltips were written to describe preexisting mechanics, many of which were once, yes, actual bugs, because of WC3's limitations, and are now simply balance and design decisions, like bottle refills can be, regardless of what you think it is, because you don't make this game.