For Boma to be such a pain in the ass was definitely unprofessional insubordination..
It could be argued this was professional
Boma was a scientist. If those meekly follow the orders of a superior scientist, they get nothing done. It's as much Boma's duty as M'Benga's to occasionally slap Spock in the face until he reacts the right way. Granted this wasn't the time or place, but it would be in Boma's professional instinct to talk back to the boss, and that's what he'd get paid for (assuming Starfleet believes in salaries).
Decent burials? Pleading for inspiration? There's a ticking clock and death looming over them and they want to die like "men not machines?"
What was the ticking clock as regards the burial?
The shuttle had lost fuel, but there was no dialogue to the effect that the leak would persist and more fuel would be wasted by the minute. The crew lacked supplies, but there was no immediate danger of starvation. The starship in the vicinity would be forced to depart in a couple of days
, after which she would be gone for a maximum of six days, and then return to continue the rescue efforts. And the natives could be kept at bay indefinitely as long as our heroes did not loiter far away from each other and from the immense firepower they possessed.
As far as we could tell, Spock could have taken a full day off to write an eulogy, draw a fictional cathedral in the sand, hold a ceremony involving solemn processions and hours-long chants, get Gaetano buried in a proper, carefully prepared six-foot hole, and then get drunk in a merry wake. There was no hurry.