You repeatedly call the jungler an AI, tell your team to join you in a forfeit, belittle the support, tell a teammate to learn to play, accuse someone of inting, rank shame, announce that the game is lost, call someone a "fuck head," announce that you're "auto piloting" (no longer playing to win)... your behavior was thoroughly unacceptable at every turn. I didn't see a single positive chat message from you. All you do is flame.
You think a month is long enough to reset a punishment tier after you've already gotten three punishments and Riot has told you in no uncertain terms that the next one is permanent? What punishment do you expect instead, another 14-day suspension? At that point a player would be spending as much time playing as being suspended. And you didn't even say that a month or two is on the border between too harsh and acceptable; it's "way too strict." How long should a player have to follow the rules to drop a punishment tier? A week? Three days?
Could your behavior have been worse? Yes. Was your behavior even close to acceptable? No. Riot told you to stop and you didn't, so your account is permabanned.
You weren't punished for misbehaving in one game. You were punished for misbehaving in one more game, in a consistent pattern of negative behavior that breaks the game's rules. Additionally, the reform card doesn't always show all the matches that led to your punishment: it randomly selects up to several matches. You might see three matches, but you also might see as few as one, even for players whose punishment stems not from a small number of egregious infractions but rather from dozens of instances of mild toxicity. The purpose of the reform card is to tell you how to reform, so it shows you an example of the behavior that prompted your punishment and explains that such behavior is inappropriate and should be avoided if you want to maintain an account in good standing.
Usually, one transgression by itself wouldn't be enough to bring such a punishment to an otherwise clean account, but the IFS works on an escalating punishment system. Breaking a minor rule, like engaging the team in useless arguments, has a minor punishment: a chat restriction. Breaking that same rule over and over again, however, doesn't prompt an endless series of chat restrictions. The severity of the punishment ramps up over time, because the goal is to eliminate the punished player's willingness to break the game's rules. If two chat restrictions don't stop the useless arguments, the system will increase the punishment to a 14-day suspension and deliver a very clear message that the continued rule-breaking is becoming a serious issue and any further instances will result in a permaban. Again, the point is to put a stop to this misbehavior. If a player is more interested in repeatedly breaking the rules than in maintaining access to their account, they'll lose access to their account.
Of course, it's possible to break major rules, like cheating, threatening people, or using chat for hate speech, and skip punishment tiers so that a clean account ends up with a 14-day suspension or even a permaban.
From Riot's support knowledgebase:
PUNISHMENTS GENERALLY FOLLOW A BASIC ESCALATION PATH:
- First Offense: 10 Game Chat Restriction
- Second Offense: 25 Game Chat Restriction
- Third Offense: Two Week Suspension
- Fourth Offense: Permanent Suspension
However, it is possible to skip to a Two Week or Permanent suspension based on the severity of the behavior in the game. Excessive negative behavior can result in a Two-Week or Permanent suspension at any time without having a chat restriction on the account.