Basically it says that in war, infrastructure shouldn't be touched. That fuel should be free. That, sadly, after the EU found that funds were being diverted it stopped paying for Gazan oil--in other words, as relief agencies are finding out, the leaders of Hamas insist that their "services" be funded first, ideological, religious, and corruption-based, before worrying about the populace.
Then again, as the article says, it's a pity that they even have a power plant, because otherwise Israel would be somehow obligated to give them free electricity. Hell, even Egypt doesn't trust Hamas, it's cash-and-carry.
One has to wonder: If the average household gets 7 hours electricity a day, how much of a reduction would powering the waste treatment facility 24/7 cause? Would it be worth cutting electricity to 6.45 hours/day in exchange for preserving what is also the Gazan facility?
Of course, the problem predates the current crisis by a decade, and isn't only due to human sewage. The coastal aquifers being infiltrated by excess pumping from that aquifer. Excess agricultural "fertilizer" is also a problem. Basically, "genocide" has caused a population explosion, which across the Arab world produced a surfeit of young adult men that triggered the Arab Spring. In Gaza, however, xenophobia and jingoism let Hamas both strengthen its position and increase resentment against the outsider.
When Israel did provide (even more) electricity, it was resented. It was to keep Gaza reliant, to bribe the Gazan population, to protect itself. An odd case of "damn you for providing electricity" coupled with "it's your duty to provide us with electricity." Gaza is apparently fenced in by one of the easternmost branches of "de Nile."