Loopback disable ipv6 - duplication

[xkpx]

Hellow gentlemens, still learning here need some help, because I think i saw something strange in watching my logs.
First is is possible somehow to disable rules that are hardcoded for ipv6 somehow and is it a good idea? ( also can i remove ipv6 from loopback routes ?)
Second i follow a guide to disable ipv6 for firewall but i still see it sometimes in loopback in example even i'am sure i disable it right.
And also on rules picture isn't this duplicating?
Thanks in advance.