1. They choose to remain ignorant.
2. They don't understand politics and try to ignore the subject.
3. They really believe that politics doesn't affect them.
4. They're plain stupid and have no idea what they're saying.
I'll explain what I mean:
Ignorance: In my view, those who don't show any interest in politics have no room to make comments. Far too many people are politically ignorant and choose to stay that way. The problem with this is that everyone has an opinion (and you're currently reading mine) but those who have no idea about what's happening in the political arena speak from a position of little or no knowledge. These folks really ought to take this to heart: “It is better to keep your mouth closed and let people think you are a fool than to open it and remove all doubt.”-- Mark Twain.
Lack of understanding: I think that the majority of people fall into this category in that politics is poorly understood. But, just like being ignorant, there's no excuse for not understanding. It takes a bit of effort but politics is far from as complex as many people seem to think and much more important
Politics doesn't affect them: I've actually heard a few people say this, and to call the person who says it 'stupid' is really being too kind. You can't help but be affected. Politicians make decisions on almost all aspects of our lives.
Stupidity: Far too many people have an opinion on politics but are just too stupid to stop and think about what they believe. The popular press does little to help by sensationalising the absurdities in politics (and yes, there's plenty of these). But I often wonder how many people actually do stop and think about or question whether what they're being told is actually the truth.
So next time someone says “I don't do politics” perhaps I should remind them that "you might not do politics but politics does you”. Whether it's through taxes, planning, school funding, the NHS, state benefits, driving speed limits, where you can and can't smoke, the price of the fuel for cars - I could go on. It's impossible to escape politics. So to say “I don't do politics” really is just dumb!