The problem is, losing sucks and if you get a bad start (or one of your allies does) it's difficult to recover, the game is generally very unforgiving.
Even over 1550 PSR you still get people that think they are the best thing since sliced bread (known as tryhards) that will shout at everyone and blame everyone else for their mistakes.
Generally as soon as the blame game starts, people concentrate more on flaming eachother and less on the game, and it's pretty much over.
Everyone that is higher up the ladder can look down on the lower guys and spot their obvious errors, happens all the way up.
The problem with noob games is that you get a massive variety of skill levels mixed together, so people spot a lot of errors and are very vocal, 1 person can pretty much lose the game all on their own and the other 4 players can just sit by and do nothing about it.
Even saying that, it is possible to win 4v5 in some games.
You gain/lose around 20-25 PSR each game, by the time you reach 1700 PSR you will generally only lose/gain ~10PSR per game, so people are generally more equal in terms of skill level.
If you want a decent game where everyone knows how to play most heroes and generally doesn't rage too much then you need to get to 1650-1700 PSR.
The other problem is that everyone wants to win, so lots of games are stacked in the hosts favour (playing with buddies etc.) or just playing below their level. People play on fresh accounts too.
There are good games to be had around 1500-1600 PSR though, but it's all relative to your own ability.
Even saying all of that, it's still a great game
