The Answer, in letters.
One Infantry Platoon does the following, and consists as such:
-REQUIRES one unit (as the book uses it) that acts as command squad (Junior officer, and 4 guardsmen. This unit is selected EXACTLY as the HQ selection, Command Squad, but with the following restrictions: You can only choose a JO (which can still recieve the Honorifica Imperialis if your a greedy sod) and you dont have access to the support squads that make our HQ's the best.
-REQUIRES at least 2 units (up to a total of 5) of infantry. Rank and file. Yes, this means a normal infantry platoon has 3 units, consisting of the CS, and two infantry blocks. They move independently, shoot independently, and are treated as separate units except for one detail: Force Organization Real Estate! We get three blocks of humans to fight what a super-human armored warrior or extraterrestrial can throw at us with just one!
The basic way of wrapping your head around it is thinking of the following: T3. Yes, toughness three. That is why we get so many more humies! BS3. This is why we get so many more humies! I realized recently the only fantasy army that matches the IG are the skaven, and if they existed in 40K, the IG would be the slaves.