A platoon leader (PL) and platoon sergeant’s (PSG’s) primary job is to inspire and influence their platoon to accomplish the mission. They do this by providing purpose, direction, and motivation to accomplish the mission and improve the organization.1 PLs and PSGs are responsible for all missions their platoon accomplishes or fails. This responsibility comes with the position, but they are only successful because of character, presence, and intellect.
Notice that it says, repeatedly "A platoon leader and platoon sergeant"
It's not about the ego of the 2nd lieuie who thinks he is charge having run absolutely nothing in his life before this. It's a partnership between him and the sergeant who got where he is, for the most part [all human institutions are fallible], by proving he could do the job.
It's similar in the Navy and it was amusing to watch the Chief Petty Officers trying to deal with ringknocker Ensigns and convince them that they did not yet know everything there was to know about life.
I tell new engineers just out of college the same. They may have that brand new degree and be just like the second lieuie that just got his/her butter bars, but the senior designer and the maintenance technician in the refinery is the senior master sergeant. Yet I have seen too much of “I have a degree, he’s just a designer”.