To show solidarity as an individual,
it is necessary to start with solitude,
to spend at least an hour a day alone,
building self-awareness, self-love,
the basis of self-enhancing action.
This is, perhaps ironically, how you develop compassion for others:
by being more aware of your own self, and developing insight into the workings of the brain,
and the thoughts that drive it from the spiritual plane, rather than the drivers from the ideological delusion.
This article about solitude versus loneliness: how solitude helps to build better relationships, seems relevant.