So, I can understand you being ready to stand in ardent defense of someone who was banned for intentionally feeding/trolling when we don't have all of the data. That's fine, I'm unsure of it myself, but I'm erring on the side that the punishment was merited largely because the fact that he got punished (which, punishments for trolling/feeding are very rare) indicates that something was more than fishy about that match beyond the Teemo pick.
So, I want to go over some of the info that Tuition Fee brought up, and I'll also go over some of the stuff you said.
- Minimal Kill Participation + Minimal damage to Champions.
This is already something sketchy. As a Support, kill participation shouldn't be so minimal, and, while I'd forgive damage in many cases for Supports...We're talking about Teemo. A Teemo who built Nashor's Tooth. Teemo Support isn't a low-damage pick, and you'd certainly expect him to have a higher kill participation than what he has.
The low damage to Champions and low kill participation tell me that, despite building a damage-focused item, Teemo made every effort to avoid fighting, not commit to fights. Plus, the majority of his damage was Magical, meaning he hardly bothered to basic attack enemy Champions with an item intended for basic attacking with. I'm willing to wager that the majority of his (exceptionally low) damage came from Blinding Dart and Noxious Trap.
- Needlessly high CS numbers
This, to me, is a massive red flag. I can barely get 60 CS as Leona in good matches where I have opportunities to CS while my lane partner is away. High CS scores as a Support often mean one of two things: 1. The match is dragging out for a really long time and you're getting the opportunity to clear waves, or 2. you're stealing shit.
You suppose that Teemo was splitpushing - well, fair assumption, but here's an issue: If Ezreal had no issue farming (he did have 134 CS by the end of the match), why was he stuck at just under two items, and why was Teemo an item ahead? Supports don't outpace their lane partners just by performing well. In virtually every case, if a Support is playing straight, they'll be just behind their lane partner, not ahead.
Between that and his low kill participation/fight commitment, I personally think that Teemo went out of their way to avoid fights, committed nothing to the fights they were stuck in, and made an effort to try to steal lane farm. Which, ultimately, amounts to trolling.
This, I'd argue is less of an indicator of an offense, and more of a compliment to the offense. On top of the very likely trolling mentioned earlier, the only person with more damage taken than Teemo was Olaf...Who had half of Teemo's death count, higher kill participation by far (50%), and is a diver, meaning he's given to less scrutiny regarding damage taken.
The fact that Teemo took nearly as much damage as Olaf, died twice as many times, and did so little damage of his own, again, points to there being no effort or commitment to fights.
Now, you claim Rengar was the reason for Teemo's high death-count as a consequence of Teemo's hypothetical splitpushing, buuuuuut, there's an issue. Rengar only killed Teemo once. Azir killed him once (while Teemo was protecting top-lane inhibitor turret), and Zilean killed him once (First Blood, surprisingly a towerdive).
The vast majority of Teemo's deaths were at the hands of Jinx. Jinx killed Teemo five times. Once under her own turret, once mid-way down the lane, once under (what I can only assume is) the ruins of Teemo's outer turret, once in Dragon pit, and once mid-way down red-side bottom lane.
Rengar may have played a part in Teemo's countless deaths, but Teemo didn't get caught split-pushing. But (and this doesn't mean I don't think the punishment is merited anymore, mind, I still believe Teemo trolled) he didn't intentionally feed, either. He got his ass handed to him and got steamrolled several times in lane.
But, even with that, there's still two questionable deaths. The dragon encounter, and a towerdive against Jinx. The dragon encounter in particular is odd to me, since Teemo died at dragon pit, and in the same rough timespan, Rengar managed to kill Ezreal and Janna near the red team's middle inhibitor turret/jungle.
Why the hell would Teemo go for Dragon while his team's pressed elsewhere on the map? It doesn't make sense for him to be so far away from the fight unless he's deliberately leaving his team high and dry.
So, all said, I personally believe the punishment is merited. I think Teemo trolled in that match, and the "Intentional Feeding" message is just a misnomer/umbrella message to cover gameplay toxicity in general.