It turned out that the MTA didn't make it easy for pioneers to earn merits by completing exploration missions in Krakatoa.
They either had to play the lottery by examining random places or use their mechs to wipe out lots of alien lives.
Granted, many pioneers had no qualms at all about the latter, but the Larkinsons were too 'honorable' to remain unbothered.
Ves fully understood why most of his clansmen would rather keep their hands clean. Even if it was hypocritical as others would most definitely complete the job anyway, the way people behaved largely influenced their ethos and vice versa.
If the Larkinsons engaged in reprehensible conduct regardless of who they targeted, then they would inevitably compromise their honorable spirit. The distance between massacring aliens and massacring humans became a lot smaller.