That's down to how you decide to act on or view the world as due to external things. Someone seeing something, having an experience, and changing their view on the world as a result of that is one thing. Dumping it into their minds is another. The fact that everyone presumably ends up with the same view after Synthesis makes it even more disturbing. Not everyone reacts to the same events in the same way, it would be creepy if they did. You disagree with me on various things. Imagine having my view and outlook dumped into your mind so that you reached the same conclusions as me. Normally you probably wouldn't even reach the same conclusions.
This pretty much sums up my thoughts on the matter, albeit with a few minor differences.
Yes, teachers, certain books, and even personal experiences can alter how someone thinks(usually for the better, but not always). For example, reading Dune, The Republic by Plato, and some of my own personal experiences(both the good and bad) over the past few years have helped shape me and changed the way I think.
My problem with Synthesis(and I'll try to explain this the best I can, I'm not usually the best with expressing my thoughts in a clear and concise manner) is that all this information from past civilizations and their experiences is just transferred into people's minds. Yes, everyone will gain from this because they have been given a better understanding of how to live, how to govern, and even how to behave. But it comes at a cost. In a sense, it robs everyone their chance to live and experience for themselves. Sure, I've had some crappy experiences and ideas in my life, but I've also learned from them and have "improved" myself in the process.
To put it another way, people now have a chance to create a true utopia. But it is just...given, and I can't imagine a more boring existence. I know our existence right now is not perfect, but we have something to strive for as a species, and this gives us purpose in life. I think utopia is a thing to strive for, but not something that should actually exist. Because if it does, what else is there to do?
For the record, I awknowledge that I might be overreacting. Maybe it doesn't completely mean everyone now thinks the same way or that utopia is now in existence. Or maybe it gives new challenges to overcome and just gives everyone a better understanding of how to live without robbing them of their chance to live. Though the EC slides don't give me this impression.
Still, I'm both intrigued and repelled by the idea of Synthesis. And I don't fault anyone for choosing it.