I believe you may proceed from a false assumption. In my 13 years here, I cannot recall having seen an instance of someone being down-voted for a nationality, or for discussing something from the perspective of a particular nationality if the discussion was conducted in a respectful, non-(abusive|mocking) manner.

In the post you refer, you provided very little context for understanding the point of view. At that time in the Chatterbox, there was actually the question if the post were meant as a joke. My own response attempted to stay with just the facts presented, including an update asking for additional information after one of your two considerably-limited responses. As to the down-votes of which you speak, they may very well be a result of the lack of context and constructive input, although some of them may be a side-effect of being co-incidental several recent posts suggesting changes to the site that, rather than providing a valid stand-alone use-case appeared (if memory serves) to be "boiled down" to the form "well, site X does it, why shouldn't we?". I can say, however, that posts that are abusive, full of "attitude", or are meant to offend will quite often garner a large number of down-votes in a very short time.

In my experience, this is generally a very inclusive community, with people who are willing to help when someone respects the fact that those here are giving of their time freely. One of the quickest ways to sour others to attempting to help, however, is to come in with a poor attitude.

Hope that helps.

Update: 2014-12-16
Changed "You" to "I believe you may" in the first paragraph, first sentence, because I realized I could be in error as well.