Having hostages or not is irrelvant. Outside of MJ, Fujitora was toying with Sabo while sandbagging. In MJ, Fuji couldn't stop Karasu or drop his signature meteor. Outside of MJ, GB can easily restrain 5 Scabbards, Momo, and Yamato. In MJ, GB can't stop or restrain Morley, even complained that he couldn't fight back. It was wven stated twice on panel that fighting in MJ is a huge nerf for an admiral.
I think its completely normal for people to give a shit about people they care about, and care less about strangers? Even Mingo hesitated when Jora was taken hostage, and he can easily kill off entire towns.