I think

More voices make a difference, lend us yours!

Or

Help spread the word, if you can!

Might read better, and they're still short enough to post quickly.

When I'm home, I'll look into creating an account or two securely and joining in. I'm already telling everyone I know about Lemmy in meatspace, it's remarkable how even my technically-adept friends are still largely on Reddit.

Oh yes, and "sad to hear/that's unfortunate" could use an endcap like "but no worries!" to soften them. Without the endcap and no further punctuation, they read negatively - maybe sarcastic, maybe passive-aggressive and uncaring, or something along those lines - I'm not really sure how to describe it at the moment beyond "negative". Personally, I like to throw in a quick example of how I understand their position, but I think that's optional.