Keep in mind that Iron Worm invasion happened during the 2nd Coalition Wars, when Saman was fighting Black River and PECS. Labi was a member of Saman's product line. Black River and PECS associated bioroids didn't sit well with that.
so... mainly bad blood between factions. But to give a specific example:
Marie and rest of the leadership of Black River (this is after ID went dormant) generally believed that Labi was lacking charisma befitting the office that she was trying to fill. This was later proven wrong as Labi went out of her way to rescue Marie No.4, which made Black River faction bioroids revise their opinion of her and started to accept her as the leader of the rebellion.
Lemonades generally follow their own agenda. They see themselves and bioroids as tools of humans... especially other bioroids. They do not see eye-to-eye with Labi who has more liberal appraoch to human-bioroid relationship. Furthermore, Lemonades refused and still refuses to accept any human as their master: they only sought to revive their dead presidents of PECS as they believed that the presidents were humans above humans... and it is only fitting that Lemonades who stand above other bioroids serve human above other humans