> Summer break isn't a period for extended homework - it's
    a chance to develop curiosity and self-development.

Yes, but for most socio-economically challenged students, it doesn't work that way. Research out of Johns Hopkins shows "summer learning loss" is greater for certain populations, and over time leads the the "achievement gap" we see in high schools. (To the extent that comparable students after Kindergarten have a one-year learning gap by middle school.)

Schools are disparaged because of a problem that occurs as a consequence of their schedule and students' home lives. IT's natural they'd want to do something about it.

I agree, summer homework may not be the best solution, but it's what they have now; it's the current limit of what we as society allow them.

(No, I might not make my kids do homework over the summer either, as I offer them other learning experiences. But then again, I might.)