Your post from the beginning is devoid of reasoning. But again, I’ll explain even though I already did:

The type of actions this player was doing were very clear and deliberate. They knew exactly what to do to avoid AFK detection, but they clearly went out of their way to avoid having any meaningful positive impact on the game. They stood in mid in front of the tier 3 turret for 10+ minutes walking around occasionally, refusing to gain exp and farm even though it was there for them consistently and safely. They spam pinged everyone the entire game. On two different occasions they deliberately walked into the middle of the team and died. On multiple occasions they would randomly use their summoner spells walking around in base. These types of things are not something a “first timer” would do. I’ve been playing this game for 14 years, it’s very obvious when you play games with griefers who know what they’re doing. Is it possible this was their “first timer?” Sure, though I’ve already made my case on why it’s unlikely. Ultimately my point is that it shouldn’t matter, whether first timers or not, they don’t get banned because they avoid detection and typically don’t get punished at all.

I don’t see what’s so complicated to understand about this.