There are issues and causes that are important to each of you, issues that you've dealt with or causes you've championed for quite a while before the possibility of this relationship ever came up. That fact makes it difficult to deal with the fact that you aren't very supportive of each other's causes. There is a lack of understanding between you, and really, a lack of respect.
You just aren't able to see the truth behind each other's important causes; you look at your partner through jaded lenses, and probably think that they're just being rebellious for the sake of rebellion itself. It stinks not to feel supported or respected by your lover in all the things that are most important to you. Your lover might start to feel as if they have to hide their activities regarding certain areas of their life, just to avoid your criticism or ridicule, or even just the subtle, slow disappointment of being misunderstood. If plenty of other factors are more in place and harmonious between you, then by all means, try to work this out. Make the effort to understand what's important to your lover and why, and to communicate your own important issues. But if there are other aspects between you that make communication or mutual understanding difficult, you might just not want to bother.