I don't believe this at all.
I don't think differences divide us.
I think a lack of respect for differences divides us, a greed for your group to have power-over is the thing that divides us. A denial that YOUR GROUP has successfully done this for ages divides us. Signs like this that deny that greed for money and power divide us with or without a person's choice to identify as a certain race, ethnicity, class, religion help those in power divide us.
I find it hard to believe that anybody not-white believes this at all. All the people of color I know understand that respect for differences is the key to unity-- not the denial of difference.
The drive for us all to be the same? Isn't that another form of wanting power-over?
"We over here have it all together, you need to be more like us" is what the peaceful edge of white supremacy says to black and brown daily!
We would all get along if we were all the same is the message is being transmitted every minute of everyday, most everywhere in the United States. But if you're in the most powerful group where you happen to live (white people), sometimes you do not realize you're failing to hear the obvious. But sometimes this attitude of we all need to be the same leads to war anyway.
I think being human creates differences between us in a natural way. I think that's a good thing. It's just that sometimes you have to reign that OTHER part of being human in -- the part that says I can't see anybody who is NOT the same as me as equal.
Soul searching is the path to peace, not seeking sameness.