Why do different cultures always blame the other one for not having enough tollerance?

Because we are all still in ignorance. Before we all have a fit. Ignorance means: Choosing to ignore fact(in this case anyway) We still choose to ignore the fact that were all human, we all share this planet, haven't found a way off it yet, maybe never will, and that until the end of time we have to share it. That means diversity will most probably always be around, and it's something we can no longer ignore.

Because they don't. No one person, culture or group is perfectly tolerant of any other. Which has its benefits, when you think about it. Discord fosters discussion, which brings new ideas and further understanding. If everyone agreed on everything, the world would be a boring place.

Pride - everyone thinks their way, culture, beliefs, or anything else you want to stick in there is better than everyone elses.