Also, people can say "Oh, but it's not a problem because if they know you can't win they have a right to walk off"
The problem with that argument is if it were true, different regions would have the same surrender rates.
Instead, we have this:
https://imgur.com/ZH09nxU
It's a society/mentality problem. If people 100% saw a loss, they'd surrender no matter the region. So why does one region have 10% and another 27.5% surrender rate? It's because of a quitter mentality, a social problem, not an odds of winning thing.
I will admit, that maybe a few regions just surrender a lot right before their nexus explodes or something similar as I don't have more in-depth stats, but that wouldn't always be the case, and there's still a huge variance.
What I do know is that at least for NA, people are very quick to walk away from potential, or even probable wins, and it sucks. What's worse is it's usually the top performer on their team that has a good overview of the game, has managed to keep a calm head, and doesn't try to surrender that gets punished.
How do I know it's bad? Because I've long since lost count of how many games I won simply because I was able to stop surrenders either on my own pre 20 minutes, or with one other and win. The only problem is, I can't do that alone post-20 minutes, and if it's that close so many times, then there's a high population that do click it, and it wont be close that many other times, it'll be a surrender without a choice.
This last surrender the first words that went through my head, and even in chat were "WTF???" because I was so confused at why my team just surrendered. How is the quitter mentality THAT bad that my instant reaction was confusion at why my team surrendered because I saw us winning at the time? Yeah, there were things in the enemies favor, but the way the game was playing out to me was a win, and I was literally playing towards that when suddenly the camera starts panning to my nexus.
There's literally nothing worse in league than "Yes we got this" instantly followed by "Oh, my team pressed a button to reduce my LP and MMR"