The thing about "forced" is that it can be soft or hard. Sure, you have the option to not say it, but how many children realize they even have that option? Your teacher says "okay kids, we have a new song to sing!" and you do it because you're a kid.

Me and all my peers said it every day without thinking at all about the words and what they mean. It was just what everyone was doing. That's exactly how they teach you to fall in line - not with physical force, but with expectation and the desire to fit in.