Our question on this verse is why is there is a need to mention all of Israel, when we already listed all these different specific categories of Israelite levels of the nation, it seems extra.
Behold, there are people who are in error due to the fact that they value and judge the importance of a person, based on his monetary status and his financial earnings. If he is a very wealthy man, they honor him greatly, and if not, they lower their respect for him/her. But in truth, we must measure a person based on his true measurements, which is someones spiritual level. What point is there in someone feeling haughty or egotistic with his wealth that HaShem has provided him/her and easier and more respectful and robust income than his friends, didn't all of that come from HaShem?
Behold, the word Netzavim (standing) in the opening verse above is hinting to a very lofty level that a person can stand on, on a very high level with strength in the aspect like the angels, which are called 'standing'. As it says -
“Thus said the LORD of Hosts: If you walk in My paths and keep My charge, you in turn will rule My House and guard My courts, and I will permit you to move about among these standing ones.
And this is why our verse says, "Behold, all of you standing here today", which means to teach us that everyone of the people of Israel can be on the level of standing, meaning to be like angels, and specifically from those that are the woodcutters and water drawers, meaning, any sort of level of income that one may have, EVEN if he is a wood cutter or a water drawer who have lesser incomes, they too can get to an exalted level, which is not dependent on what income level HaShem has bestowed upon you. The reason is that all individual Israelites which are all apart of the greater house of Israel, and for each individual, they are literally carved out and are a piece of our Lord above. And since its within our ability to reach this exalted level of 'standing', which is being like angels, therefor, one should never show haughtiness or that he is better than his friend, even if his income and financial status is not like yours, and this is correct with the help of heaven.