Women and men(both little and small) cared for anyone not at all (5-6)
Cummings makes a point of saying how people in anyone's town don't care about him at all. It's not like he's a bad guy or anything. These other people are just too wrapped up in their own lives and their own families.
they sowed their isn't they reaped their same sun moon stars rain (7-8)
The parents of the pretty how town have kids, and they raise them all in pretty much the same way. This leads all the kids to be similar. Of course, they'll grow up one day to be just like their parents and not care about anyone but their families.
someones married their everyones laughed their cryings and did their dance (17-18)
The people of the pretty how town get married and do all the typical stuff: they laugh and cry and dance and all that. Then they grow old and die. Somewhere along the line, they have families and start the whole cycle of nature all over again.
and only the snow can begin to explain how children are apt to forget to remember (22-23)
Cummings suspects that children grow up to not care about others because this is exactly what they've been trained to do by their parents. If their parents only care about them and their family, the kids will obviously grow up to repeat this same pattern.
busy folk buried the side by side little by little and was by was (27-28)
The people of anyone's town are nice enough to bury him after he dies. But that's about it. Now they have to get back to their busy little lives and raise some busy little kids. Then the kids will grow up to be busy and they'll have busy kids too. Well, you see that this is getting us nowhere.
Women and men(both dong and ding) reaped their sowing and went their came (35-36)
The women and men of the pretty how town bury anyone and noone. Then they get back to their comings and goings. Life is all just family and business and no one ever stops to think about the bigger picture. Well, that's what poets like Cummings are here for.