I still think you're missing the point here.
1.) No one is making people stand it will always be a personal CHOICE
2.) No one is saying people standing is going to fill the stadium, however, it is widely proven that when you're standing up you're more likely to start singing and chanting (You'll know this if you've been to a Villa away game)
3.) Hillsborough is irrelevant, we're not going back to terraces. Terraces were dangerous. This is called SAFE-standing for a reason.