As other, wiser people have said, there are at least five reasons that this sort of need to turn everything into an anecdote about how great it is to be a parent. If you'll allow me, I'll list them in my own words:
- Latent misogyny: We first off have to remember that Elly thinks that marrying and having children is simply what women do because she was raised to think that way. Despite being friends with a single mother and getting along well with childless-by-choice Georgia, she still thinks of Connie only becoming complete after she married Greg and still mourns the fact that no one will love Georgia when she gets old.
- A need for sympathy: While she thinks that she had to get married and have children to be a proper adult, Elly has always resented the fact that she has to live for others first and herself second. By ranting about her sacrifices and how little appreciated she is, she can at least get people to feel bad.
- A need for legitimacy: This seems especially important because she is right to say that most of the people around her don't seem to see her as mattering worth a damn. When she mommy-jacks, she can tell herself that John has no right to act as if what she does is mindless and thus unimportant.
- A need to be validated: The reason for her need to feel as if she does do something important is that she wants to be reassured that she made the right choices in life. By hammering home how critical it is for proper ladies to do what she did, she can silence the voice that wants to yell the Hell with it and leave.
- Envy: The fifth reason she mommyjacks was revealed when she started salivating in glee at the idea of Phil being as miserably monogamous as she reveals a need to avenge herself on anyone she perceives as having a better time than she is. If she can't have fun because she's stuck at home with the brats, every other woman in the world has to have kids so they can't either.
This means that April can look forward to a lot of chirpy commentary about how she's living her life all wrong from people who aren't honest about why they say that.