To be raised on something is for it to be something which you were taught as a child. It means something like "been made accustomed to as a child." It could also be what the child ate, in other contexts.

It is part of a phrasal verb. 'Raised on' means reared as a child in thinking that birth (population) control is right.

It could have been worded and phrased better. But it could be difficult to convince a generation raised on ideas that population control amongst the natives is disastrous for the country and scared witless by it from the media, that high inflows of immigrants are desirable. Often English has to have long sentences to explain things fully, and also it often requires to be writing in a short and concise manner. Or simply changing the order a little. But it may be difficult to convince a generation scarred by population control and raised on this notion. That high inflows of immigrants are desirable.

Eric From Canada's explantion is correct!

It’s not necessarily the meaning of “on”, it’s more about the use of “raised on” as a way to express something that you were very accustomed to growing up. Someone can say: “I was raised on nothing but peanut butter sandwiches”. It’s basically something that you’ve been used to since you were a kid and it was the norm. So it might indeed be difficult to convince a generation of something that is different from what they’ve been accustomed to their whole lives. 🌈