Unable to boot Kali linux using rEFInd
I am not sure how you doing what you have posted. Also, I question the wisdom in doing so.

I assume you installed rEFInd on your internal drive to be used to boot Kali Linux on a flash drive. You intend to use the flash drive to boot Kali Linux on other machines. How do you know if the other machines have rEFInd? If rEFInd is installed on the other machines, how do you know if rEFInd will be configured to scan for new operating systems to boot from? How do you know if the other computers will not be password protected to prevent you from booting from your flash drive?

I download the kali-linux-2018.3a-amd64.iso file from the Kali Linux Downloads website. I followed the instructions for OS X given on Making a Kali Bootable USB Drive website. In other words, I executed the following command.

sudo dd if=kali-linux-2018.3a-amd64.iso of=/dev/disk1 bs=1m


When I run the command diskutil list disk1, I get the following. 

/dev/disk1 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *15.7 GB    disk1
   1:                       0x17                         3.2 GB     disk1s1
   2:                 DOS_FAT_12 NO NAME                 720.9 KB   disk1s2


When I run the command sudo fdisk /dev/disk1, I get the following.

Disk: /dev/disk1    geometry: 1912/255/63 [30720000 sectors]
Signature: 0xAA55
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
*1: 17    0   2   1 - 1019 190  32 [        64 -    6234176] OS/2 hidden 
 2: 01 1020   0   1 - 1020  43  32 [   6234240 -       1408] DOS FAT-12  
 3: 00    0   0   0 -    0   0   0 [         0 -          0] unused      
 4: 00    0   0   0 -    0   0   0 [         0 -          0] unused      


I can EFI boot this flash drive from the Startup Manager. When running the same version of rEFInd you are using, I get a different icon and text label than you posted. I can boot this flash drive using rEFInd.

I realize I am using a older 2011 iMac, but I find it strange that our results differ so much.