Public Bus should not bring too much things besides passenger's

Today I came in To Cambodia through Poipet-Thai Border. I got my passport stamped about 1 pm. I got a motor-taxi and he brought me to a bus with 2 stories and I paid about $6.5 us. The bus leaving to Battambang at 1.30 pm.
When I got up to the seat near the back, I saw few rows of seat were occupied by plastic bags full of fruits. The air-condition was not very cool. About 1.30 pm the bus was still at the station.
Latter again they loaded more big plastic bags with fruit. until you couldn't see the back screen.
They added more plastic bags full of clothes. They put 2 more bags in front the front seat .
At last the bus slowly moved, the bus was overload with fruits.
About 3 pm  some passengers went down and they picked more passengers. Almost 330 pm the bus stopped at the road side, then I went down to urine. I saw the drivers were changing the tyres,  oh my God.
I made a quick decision and I stopped a taxi and continued my journey. I reached Battambang before 5 pm.

Those bus have over loaded too heavy thing and even blocked the stair. The bus never concern the safety of the passenger. I will never use this kind of bus again and I dont know the fortune of other passengers...Who are to blame ???