WEBRip-1080p and WEB-DL1080p

I understand the definition of the Rerips. What I don’t understand is:

1 - If WEB-DL is better than WEB-RIP, why would a (proper, rerip, real etc.) replace the better quality release? It is my understanding that WEB-DL is of a higher quality than WEB-RIP, or do I have this wrong?

2 - I can’t seem to remove WEB-Rip from the group, but as you made reference to, you must have more than one, or else it defeats the purpose of a group. I would prefer to just stick to WEB-DL, but I can’t seem to accomplish this.

Regards,

Shedrock