If you are not willing to protect your country then you are not willing to protect the values it stand for... Simple as that. That is of course good when those values are not wholly good.
But at the same time politics should not just be put in the backseat in terms of not serving, but also in terms of protecting people.

If I lived in a country under a despotic ruler who liked to oppress other peoples and dissenters, I would still serve if it protected my people from horrible devastation (think terrorbombing for instance). As noted the people shouldn't as a group suffer because of the regime, and I would protect against that.

Btw, I have served my constription in the Danish Royal Navy.