upstream libreswan supports an alternative KLIPS IPsec stack. This stack was never supported in RHEL. But userland was built with support for this stack so customer who wanted to use the alternative IPsec kernel stack could do so without recompiling the libreswan userland.
Upstream is disabling KLIPS support per default and will remove it entirely soon.
Therefor, remove the userland support from libreswan in RHEL8. This should affect no regular users of libreswan with RHEL.