Here is their justification:

In order to maintain security for our users, the Authy application does not allow importing or exporting 2FA account tokens.

Users who want to import or export their tokens can follow this process:

1. Login to the desired online account with your existing 2FA token.

1. Disable 2FA in the app’s site.
2. Re-enable 2FA again in the app’s site.
3. Scan the QR code, optionally write the Authentication Key, this time on the desired 2FA App.

https://support.authy.com/hc/en-us/articles/1260805179070-Export-or-Import-Tokens-in-the-Authy-app