I just got paired against 3 level 30s and 2 level 10s while I was duo queue-ing with a friend both level 10. I was on my lower leveled account just so my friend wouldn't have to face higher levels.
I was dead wrong.

I mean, if this is how fair it's going to be while matchmaking, why not pair us with the pros while you're at it? Because this system is severely flawed.

Our team was all at negative score except me as Irelia with 9/6/5.
We had a jungle Sejuani who died at blue buff even after I gave her a good hard leash in the beginning.
By the time I went to my top lane, our Master Yi gave first blood to enemy Ezreal. That's not all, Yi said "f*** this" and started to feed intentionally.
By the end of the match he was at 3/12/1 because he was ignoring my warnings, MIAs, and facechecking.
After a few more deaths in the jungle by Sejuani, she left the game with her inventory full of Doran's Shields.
You guys get the idea...

So, why do I keep getting unlucky matchups and fall victim to trolls and immature players? Even on my main account (this one), I encounter many of these feeding/trolling/immature players at level 30.

Should I even be putting my time and happiness into a game that I truly enjoy playing but is shattered by the community?

I know you're being honest but two lvl 10 players being paired up with lvl 30's is just not seen alot so getting riot to do anything would be quite difficult. If it happens again though, try taking screenshots of the stats lobby after the game.

How many times did you queue with your buddy?

I think there's this question about 3 times a week here.

Lower levels can queue with higher levels, so the matchmaking system figures out an in-between based on your Elo. If you have a level 30 friend you're queuing with, or if someone on your team queued with a lower level player, you're going to face higher level players. There's nothing to fix.

If you do not want this to happen, then queue with more people around your level rather than solo queue.

This is also an opportunity to learn. Why did you lose? Are you blaming your team for doing something intentionally, or is the other team just playing better than your team is? What could you have done better? How were they getting the drop on you? What could you have done to prevent it?

... It has built in smurf detection? When did this happen? How long was I gone for?

so... op made a smurf

the system detects a smurf and match it against lvl20 and lvl30

I don't see the problem here

Remember the screen after account creation asking you: "Are you an experienced player? not at all/yes/yes, very much"? :P

It's really easy to detect smurfs you can see in their cs builds and overall kills and assists maybe riot figureout a way to check this things and detect smurfs