Handling blank user agent requests

I have been working to setup The Events Calendar Event Aggregator but was not able to get it to ingest media from my site. After quite a bit of research I have discovered that this service requests the media using a request with a blank user agent. By enabling HackRepair.com’s banned list of user agents, blank user agent’s also get banned via the third line in this section of the .htaccess file.

# Start Abuse Agent Blocking
RewriteCond %{HTTP_USER_AGENT} “^Mozilla.*Indy” [NC,OR]
RewriteCond %{HTTP_USER_AGENT} “^Mozilla.*NEWT” [NC,OR]
RewriteCond %{HTTP_USER_AGENT} “^$” [NC,OR]
…

My questions are
1.) How can I disable this particular user agent blocking rule while retaining the others? Is there a User Agent whitelist within iThemes Security?

2.) Considering that bad guys can easily set their own user agent, and that legitimate requests may come with a blank user agent, is this specific blocking rule still commonly used and viewed as valuable?

Thanks,
Mark