I very much doubt that the Swedish school system can be seriously described as despicable or horrendous, even if it has fallen from its former glory. Would you care to elaborate?
The second major issue is that they are a tool the state uses to indoctrinate children (naive by nature) with whatever the correct values of the day are. Prussia (where public schooling originated) needed obedient soldiers, modern-day Sweden needs a large underclass of socialists willing to support various hare-brained political schemes. The schools reflect this. What happens, for instance, if you call homosexuality "not normal"[1] in a Swedish school? It gets you an F in biology and a label as a "homophobe" in the state-run media[2]. One wonders what happened to students who questioned communism in the Soviet Union.
See "Deschooling society" by Ivan Illich, "Underground history of the American school system" by John Taylor Gatto.
[1] Which is surely true, statistically speaking.
[2] http://www.svt.se/nyheter/regionalt/abc/homofobi-gav-underka...