Your opinions and beliefs only have a point to one person without fail and that's yourself. For them to matter, be worth while, have weight, or have a point to anyone else requires that person to actually feel a reason to give such credance to your opinions/beliefs. That can happen in a variety of ways. It could happen simply because the person already thinks very similar to you. It could happen because you provide evidence enough to convince someone. It could happen because your past record has shown you to be an objective person that has good beliefs/opinions and thus are given a level of trustworthyness. Etc.
Your opinions matters and are important to you and only you by default. For everyone else, there needs to be a reason. The only thing "pointless" with regards to opinions is expecting that people are going to give a damn about them without you giving THEM a reason. Mind you, giving THEM a reason...not giving a reason that YOU feel is good enough but doesn't mean dick to them. That's the other problem people tend to make, they throw a reason out why their opinion should matter that suits THEIR standard...but that doesn't really matter becuase you're not trying to convince yourself.
You're not going to convince a millionaire to do what you want because you offer him $1,000 dollars because in your mind that should be good enough, because he's not movitated by that. You have to figure out what it is that would motivate him if you really care about getting him to do what you want.
As far as being objective and having a political belief...again, I think you're incorrect. Its entirely posisble to be objective and have a political belief, however its more difficult to do the more engrossed you become in that belief and the more you wrap the belief into the very fabric of who you are. I know a number of objective liberals and conservatives, many right here on this board. Sometimes even just acknolwedging your difficulty in being objective due to your vantage point in and of itself helps lend to objectivity. Being objective and having a strong belief, in whatever be it politics or something else, is possible...its just not easy.