Exactly. Explain me why do flathead screwdrivers exist, if there are phillips head screwdrivers. I don't have a problem with mastering a new tool, but I do have a problem with mastering a tool purpose and idea of which I do not fully understand.
I would suggest that the onus of learning this isn't on other people though. You can start with a baseline assumption that there is a reason these decisions are made. Assume other people are smart, rational actors, and that certain pressures and tradeoffs lead to the belief that the current strategies are the best we have for the state of things overall.
The reason I say this, in particular, is that you questions and answers in this topic have felt close minded and defensive. I say this not as an insult, but highlighting that this is often how I approached things when I was early on in my career. I felt overwhelmed by all the things I needed to know, and wasn't even close to having a mental model of how all the things in a fully working piece of production software fit together. That imposter syndrome led to me discounting things I didn't understand because it was emotionally safer to feel like I knew better than to accept I was barely floating along. Was this thread about a good faith effort to understand why terraform is needed, or is it a rant for why you're mad you have to learn it?
Edit: Phrasing.
However, in the mean time, it's always worth coming at these things with the generosity of mind to assume that smart people made tradeoffs for real reasons, and for your "day job" work in the frameworks adopted until you understand the problemspace well enough to give truly informed feedback on why to do something differently.