These things aren't even comparable, I have no idea where you think the irony lies.
House wall: - keep pesky neighborhood kids from running through it and ruining your grass - keep your neighbors from being able to see you while youre swimming in your pool
Border wall: - attempt to keep Mexicans from immigrating into the country illegally
I fail to see how these use cases are at all similar. Please, if I missed a use case for a house or if your home is constantly being attacked by barbarians let me know, but I don't think anybody in California builds a wall to "defend" themselves.
Not according to what I read on Nextdoor. The people talking about making their walls taller, better, covered in more cameras don't care about the neighbors. It's about keeping strangers out.
That's because you don't view Mexicans as pesky neighbors trampling all over your country.
The only thing similar about these two contexts is the word "wall".
I don't think a border wall is a good idea because it will cost a lot, not solve the immigration problem, it symbolically means a lot in terms of diplomacy and there's better solutions. Also, a lot of these people just want to escape from local conflicts, poverty, etc.
My parents bought window railings because although they hated how they looked, they were cheap, solved the problem and, I mean, these people just wanted our TV and my mom's jewelry.
In my case it was railings cause we didn't live in a house with the square footage for a garden lol. But I guess for all the well-off folk with gardens and steal-able stuff in their gardens, fences ("walls") serve a similar purpose?