The thing is, everyone who plays League has a life outside of this game. And the other four players on your teams suffer when you leave games, whether it is due to a connection issue that you cannot control, or because you chose to disconnect. If you know you have connection issues, then you know what the risk is when you queue up to play a match. It may seem a bit harsh to say it this way, but if you knowingly make that choice, then it's up to you to face the consequences of that choice, which is a LPQ penalty that escalates if you continue to leave matches.
And as far as having a life.... well, to be frank, if you don't have time to finish a match, don't queue up for one. Or if you do queue up for matches, but abandon them because you decide to go do other things, don't complain if you face the consequences for leaving the matches.
It's pretty rare that you will find players who actually like it when they have a d/c on their team, or when they have to play 4v5, or 2v3. It makes the matches infinitely harder, and in some cases completely unwinnable. If you spend much time on the Boards, you will see a fair amount of squabbling between players as far as what exactly is considered "negative" or "toxic" or what constitutes this rule violation or that one, but what you will almost always see people agreeing on is leavers/afks. About the only people I ever see not agreeing about it are the ones who are under the 20 minute LPQ, like yourself. In game, you can have a team that is screaming at each other, but let one person quit or disconnect and all the others will pipe up with "rprt x9 plz thx." It's the fastest way to make a team work together. Too bad it involves putting the team at such an amazing disadvantage, and has the potential to tilt some players into oblivion.