Looking at CapnJoe's script, I realized it would just not work as posted, especially if invoked with "sudo .\UninstallSynergy2.sh" command, since the backslash has a different meaning in bash shell on MacOS. If you run it as shown, the $USER variable becomes 'root' which will NOT remove your ~/Library/ directories as you intend.
Here's a better version of the script:
#!/bin/bash
sudo launchctl unload /Library/LaunchAgents/com.symless.synergy.synergy-service.plist
sudo rm -rf /Applications/Synergy.app
sudo rm -rf /Users/$USER/Library/Preferences/Symless
sudo rm -rf /Users/$USER/Librar