You don't need insync - most people just automate rclone sync commands using whatever task scheduler their system runs by default (cronjobs or systemd units, typically). For those who prefer a GUI, KDE has a Scheduled Tasks app.
On Android, you can use Round Sync which is a wrapper around rclone and can import the same configs.
Email blocklists are based on spam and malware.
I've never heard of an email operator refusing to send or deliver SMTP messages to/from a certain provider because too many of its users support the wrong political party.