why do bikers think that they own the left lane?

So i was driving in mumbai like any other day and i try to maintain my lane despite all the dumbasses who drive on the lines. I needed to take the next exit so i changed lanes so i could be in the left most lane, there was a very small gap to the left of my cars and bikers kept using it to overtake from the left which annoyed me because it’s extremely unsafe so i strayed left and shut that gap. Soon after that the bikers started honking and didn’t stop i could see in my irvm that a lot of them had huddled up behind my car. A few of them started overtaking me from the right which is what they should be doing but most of them made hand gestures and hurled insults towards me some even knocked on my car’s windows and slapped the bonnet. Why is this behaviour tolerated? Basic road manners are missing in most people and it’s so sad. (Forgive me if i’m wrong i’m not very experienced)