Depends on what you mean by 'valid target'. Since the twins' actions don't really serve to get rid of her or protect the other students from her, they smack of simple vengeance or two wrongs making a right. That's very human, but valid?
Who else was going to take a public stand against her? By making themselves mavericks and outlaws, the Weasley twins have ensured that they can afford to show her up when no-one else can. Sure, it's vengeance, but the Umbridge regime was such that someone needed to make a stand. (Pity it had to be Fred & George, whom I personally find annoying, but I would have applauded whoever had done it.)
That goes doubly for the Dursleys, whose cruel treatment of Harry is only likely to increase if they have more negative encounters with magic folks. Dursleys + Twins = vicious circle.
The Dursleys started it by mistreating an innocent baby and shutting Harry in a cupboard for much of his childhood. Had they not been such sadists to begin with, I would agree with you that the Toffee was calculated to wreck Magic/Muggle Relations. However, the Dursleys were the ones to begin that particular process, so I can't shed any tears for Dudley getting "stung" after an act of thievery.
Re: Devil's Advocate Time
Who else was going to take a public stand against her? By making themselves mavericks and outlaws, the Weasley twins have ensured that they can afford to show her up when no-one else can. Sure, it's vengeance, but the Umbridge regime was such that someone needed to make a stand. (Pity it had to be Fred & George, whom I personally find annoying, but I would have applauded whoever had done it.)
That goes doubly for the Dursleys, whose cruel treatment of Harry is only likely to increase if they have more negative encounters with magic folks. Dursleys + Twins = vicious circle.
The Dursleys started it by mistreating an innocent baby and shutting Harry in a cupboard for much of his childhood. Had they not been such sadists to begin with, I would agree with you that the Toffee was calculated to wreck Magic/Muggle Relations. However, the Dursleys were the ones to begin that particular process, so I can't shed any tears for Dudley getting "stung" after an act of thievery.