i wish i could state my view on the subject, but doing so would break *several* rules on conduct of the board about religion and politics... and i am not prepared to do this.
i will, then ask you a couple of questions.
do you think that people truly, honestly believing that they are doing something good should get away with any damage they caused, because their intentions are or were good?
do you think that it's impossible that a objectively good action can cause a lot of bad consequences, in the long, or even the short run?
do you think that something is good when it responds to the letter of some philosophical or religious convention, or when it has good effects on the society at large? or do you think that both these conditions have to be fulfilled for an action, or a man, or whatever, to be dimmed "good"?
what happens when there is more than a philosophical/ religious set of conventions active at the same time in the same society? what if the idea of what is "good" for one conflicts with the other? who decides what is good?
maybe i can do an example about this last questions that won't offend anyone. you will excuse me if i use some italian names, but i have no clue of the english equivalent (i'm italian).
the dulcinians, a religious sect active between 1300 and 1307, believed that christians should refuse any gerarchical order, because all men are equal in front of god. they also believed that good christians should be poor, because rich men have a much more difficult time to attain eternal salvation, according to a very famous passage in the bible (the one about the eye of the needle and the camel... "è più difficile per un ricco arrivare in paradiso che per un cammello passare attraverso la cruna di un ago" in italian. you figure out the english equivalent.

). finally, they decided to put the preaching into practice by... ehm... challenging the social status quo and robbing the nobles of their riches.
notice that this was a good act.
the nobles did not deserve their riches. the nobles used their power to cause sufferings for the poor part of the population. most of the church, and certainly pretty much the whole clergy in rome (which ran the show) was corrupted. in the end, after a short period of adjustment, everyone would have been on a much better position to receive eternal life, AND the social organization of the world would have been much fairer.
pope clemente V (clemens?), called a *crusade* against the duclinians.
they were killed by the hundreds, tortured, burned alive, and so on. they went properly "medieval" on borther Dolcino and the other heretics, if you wish.
now, that is also a good act.
the entire social structure was in dange of collapsing, leaving entire regions into chaos. the dulcinians might (or might not) have had good ideas, but they did rob and kill to enforce them. finally, one might argue that one that is forced into "salvation" has not really been rescued from evil at all. the whole deal was simply killing people, stealing their riches and get in their position of power, with Dolcino being the new pope and his trusted men running the show.
who was right and who was wrong? were they all wrong? and why can you tell with any certainty?