“We can disagree and still be friends” only works (and then it is a good sign of political culture) when both sides agree to respect each other as equal citizens and acknowledge to have the same rights. The “friend” relationship is generally perceived as an equal one - in this case it is implied, but might (depending on the context entirely) be anything but that.

I don’t know where the pic from OP comes from, but I think it’s a pretty clever caption.