Simple enough.
Invite Patriots, thereby opening the doors for Antifa to infiltrate, and he knew that.
There were plans for Antifa to storm the Capitol. Someone posted a screencap of a mobile shot of NPR making announcement at 9:33 am about 'patriots storming the Capitol' which, as we all know, didn't occur until later in the day. This was then used as an 'excuse' by many, many House and Senate members to 'change their votes' because muh storming the capitol and we can't have this!
Loeffler was one.
Pic of NPR posted and notabled earlier.