Try being empathetic and place yourself in their shoes.,its not that they relearn the game every new champ, its that they have a lot more to actively think about than you.
Learning a new champion means you're leaving your comfort zone and that means you have to spend active thought on everything you do as that new champ.Laning, teamfighting,and even just rotating around the map can be completely different depending on the champion you're playing. Junglers are a strong example of this just compare the movement and ganking patterns of lee sin to someone like fiddle.
Which means there's less time for your brain to think about the other fundamentals for winning a game. If you're thinking about which levels are where you have a higher power spike than your lane opponent, you're not gonna be thinking about the timings of dragon and buffs.
Just be empathetic its not that they don't know that stuff trazz, its that they have less time to think about it compared to you on your comfort pick.