I don't think joy and civic mindedness are mutually exclusive- I had a whole list of historical figures I admire to back up this point but then I thought that would just spark another debate about their merits and how I know they were joyful, lol.
I will just say that joy and contentment are not the same thing. I can be joyful and grateful for the life I without putting on blinders and seeing that there is suffering in the world. Heck, there is suffering in our own family right now. I am sad about some of those things, I am angry about others. But I still take time in the day to express gratitude, to keep my perspective, to meditate, to pray. These things keep me grounded in joy while I still face the world head on. I am actually much more productive in my pursuits of community service and social justice than I was before.