It's simple: Because Moriah is an evil pirate. He wouldn't give a crap what Absalom does to his subordinates or to Perona because his goal was simply the most important thing for him.
He was stealing the shadows of so many people; destroying their lives for his own personal gains. Thus, Moriah is a villain for a reason.
On the other hand, Moriah did take a turn when he sailed to Hachinosu alone to rescue Absalom, so he did care for his subordinates or did he have a change of character at last, after being betrayed by the World Government?
Yeah you're right, I forgot these assholes are evil to begin with. They reap what they sow. Hes just an example of a villain who can care for his own men, nothing more. He could have had a change of character, that would be interesting but Im not holding out for it, especially since Oda just offscreened Perona finding him and reuniting with him on Egghead, unless something has gone horribly wrong there too and Peronas got captured and even killed by Devon too and added to her collection?
Im absolutely dreading the fact we've not seen Devons collection of decapitated womens heads and someone we know is gonna be joining it as a shock reveal to coincide with Oda revealing the collection for maximum emotional impact. Perona could be that victim. Ive legit feared it since she set out to find Moria and thus head to Hachinosu. Somehow she got there alone without the BBP even noticing and taking action to lol.
Moriah was legit evil during TB as you said too, the shadow stealing, ruining Brooks life even more, letting people be destroyed by the sun and becoming just as merciless as the one who slaughtered his crew in the new world ultimately, (presumably Kaido ofc).
Id like to think he was protective of Perona and if Absalom or anyone tried to do shit to her, he would give them hell but man, its easy to forget how much scum these characetrs can be and are too.