That's correct. As I said, even a round home button could be an issue for someone. That's doesn't make it a design flaw.
I don't think they took it with too much consideration. I think it's definitely a flaw in the design, but not something they thought would be a problem for the majority of the userbase.
I can't think that they made is specifically to have the vibration feel the way it does. I think they designed it, noticed it, and figured it would pass the majority.