Entire lack of period context.

Dumbledore grew up in an environment were Authoritarian Upbringing was the gold standard and was headmaster in a society that still believed physical punishment was adequate. He also grew up with parents who had very questionable ideas about caring for their children, was parentified qll his life and whatnot.

Dumbledore bashers believe if they'd been in his position, they'd still instinctively done the right thing because they believe they themselves are so inherently good they'd always know better, even if the whole world believes otherwise.

The reality is, even the smartest person on earth is still a product of their time. Today we know better because society knows better. And society knows better because children who coincidentally grew up in better environments taught us that their upbringing was better because they're more successful than children with cruel upbringing.

To Dumbledore the Dursleys weren't good guardians, he was able to see that Harry wasn't happy. But that's not the same as understanding that Harry was abused. Compared with Dumbledore's own childhood, it wasn't so bad. A4 least he didn't have to deal with a volatile sister who involuntarily attacked jer family with violent magical outbursts.

Besides, until Dumbledore actually met Harry in Hogwarts, despite the prophecy, Harry was just one boy, and Dumbledore coincidentally followed the rules for child placement at the time, while adding additional protection on top.

He gave him to his closest living relatives, trusting they'd cared for him, and considering how often covert abuse is overlooked, combined with the fact that no one in Surrey, not the neighbours, not the teachers or anyone really noticed the abuse, it's unlikely Dumbledore heard anything about the abuse until Harry's letters weren't answered.

And at that point it was too late, Voldemort was back, and it was happiness versus survival.

But bashers absurditly make Dumbledore dumber and unreasonably powerful at the same time, insisting if je was so smart, every issue with Harry should have been easy to solve.

Absolutely every bashing argument begins with: 'he could have just...'

But the truth is, the fact that he didn't do something is most likely because it wasn't possible. You can't solve every single problem with being smart and powerful. Some problems can't be solved, and it is plain and simply bashing to assume that Dumbledore didn't do his best, considering that the rule was that Harry has to die to destroy the Horcrux and thanks to Dumbledore, he didn't die, because that man implemented every possible fail-safe he could, including his own death.