I hate this concept of "political voting". I understand and acknowledge that it is present in the contest - with some countries benefitting/being targetted more than others. I also acknowledge that the diaspora factor is present in the overall Eurovision experience, but I think people give it too much credit.
I bet the "political voting" attitude is perpetuated by the broadcasters (like BCC) whose commentators tend to inject their personal cynicism into the contest, and pass the attitude along to everyone else who watches. This whole idea of "it's all political voting" is a part of the greater victim mentality of entitled countries who want to put in the least amount of effort into a song and expect great returns. Then they start hissing when people vote them down or don't react positively to their half-assed effort.
There's also the concept that peoples' tastes and general attitudes towards things like music are fluid and transcend man-made boundaries. Several things account for a populace's musical preferences. All of the countries of the Soviet Union were under the same government and had shared media, music, and pop culture, and a generally common understanding of what constitues "good music". To this day, there are songs and artists that are enjoyed throughout the ex-USSR countries, even with the overtly hostile political situations amongst many of them. Same goes to the former Yugoslavia. In addition to a shared past, there is a large population of people throughout those countries that understand Serbo-Croatian, and it's obvious that you're more likely to like a song in a language you understand than one you don't. Even the Nordics, in my opinion, tend to produce similar types of music and artists with similar aesthetics, and when this manifests itself in Eurovision, you see them giving each other points. The same can be applied to other subjective things like interior design - Nordic countries are more likely to appreciate Scandinavian minimalism in their decor than someone in, say, southern Italy. That does not imply political bias, that just means that peoples who are closer to one another culturally and linguistically are more likely to have their tastes informed by the environment in which they were born and raised/socialized.
The strong performances of several previously-uncompetative Eurovision countries in recent years prove that if an entry ticks all of the right boxes, it will get international support. Never in a million years would I imagine that Portugal would receive Armenia's 12 points, but it happened because Amar Pelos Dois touched millions of people across Europe, and compelled them to vote for the song for its merit. Even the UK was rewarded with Jade's strong showing in 2009, and that was a very competative year.
People need to stop blaming "political voting", and realize that peoples' tastes are informed by things other than their countries' political disposition (like shared culture, language, understanding of what constitutes "good" and "bad") and start putting forward a sincere effort if they want good results/to win.