https://worstgen.alwaysdata.net/for...vernment-akainus-character-got-exposed.18324/
Lakainu is ok with doing business with Pirates, he was against the removal of Shichibukai while Fujitora wanted to remove it, and he is the no.1 Larine dog of the Celestials, that's the only reason government supported Lakainu against Aokiji while Aokiji was supported by Sengoku and other Larines.
Lakainu also killed civilians
just to protect his Celestial Dragon masters at Ohara, Ohara people were not pirates yet Lakainu killed a lot of civilians too.
Your assumption on Lakainu can burn down nobles etc based on him learning they are doing business with pirates is nonsense.
Lakainu only complained when Doflamingo was treated like a Celestial Dragon, which would make Doflamingo as Lakainu's master, Lakainu just didn't want to be a subordinate of a weakling pirate like Doflamingo, that's all, but perhaps he can agree to join a Yonko like Aokiji did. After all Yonko > Ladmirals and Lakainu.