Two thoughts.

1. In any relationship where I have influence, I expect to get more of what I model.

For example, in a community where I have influence, I expect demonstrating explicit support to push community norms towards explicit support, and demonstrating criticism to push norms towards criticism.

This creates the admittedly frustrating situation where, if a community is too critical and insufficiently supportive, it is counterproductive for me to criticize that. That just models criticism, which gets me more criticism; the more compelling and powerful my criticism, the more criticism I'll get in return.

If a community is too critical and insufficiently supportive, I do better to model agreement as visibly and as consistently as I can, and to avoid modeling criticism. For example, to criticize people privately and support them publicly.

1. In any relationship where I have influence, I expect to get more of what I reward.

If a community is too critical and insufficiently supportive, I do well to be actively on the lookout for others' supportive contributions and to reward them (for example: by praising them, by calling other people's attention to them, and/or by paying attention to them myself). I similarly do well to withhold those rewards from critical contributions.