The concept of a Power Flag on my schematic bothered me at first also; and while I do think some things could be done to improve it, it makes sense once you understand the basics.
The Power Flag allows for ERC checking while using generic Symbols. If you want to remove the Power Flag from the schematic you can create something KiCad users typically call an “Atomic Part”.
Every EDA program has it’s own individual quirks.
Realize that you can become a Developer and make the changes to make KiCad what you want it to be.
Welcome to the forum!