Why is Bronze 2 full of trolls and afks?

I've been in Bronze 2 ever since the promos. Although I know that the system changed, I feel that it is still stupid to be in Bronze 2. I was demoted to Bronze 3. Took 5 games to get out. Meanwhile I have played 40+ games in Bronze 2 and lost more than half. On top of that, people were better in Bronze 3 than Bronze 2. Lastly, 2/3 games in Bronze 2 I lost because of afks and trolls. Meanwhile there were no trolls in Bronze 3 and one afk who got back at 7 minutes. Please find a way to punish people more for such actions instead of then having no loss for making me and my team or the enemy team lose LP because of one person.