The Merchant of Venice - Shylock part 1

Shylock. He hath disgraced me, and
hindered me half a million; laughed at my losses,
mocked at my gains, scorned my nation, thwarted my
bargains, cooled my friends, heated mine
enemies; and what's his reason? I am a Jew. Hath
not a Jew eyes? hath not a Jew hands, organs,
dimensions, senses, affections, passions? fed with
the same food, hurt with the same weapons, subject
to the same diseases, healed by the same means,
warmed and cooled by the same winter and summer, as
a Christian is? If you prick us, do we not bleed?
if you tickle us, do we not laugh? if you poison
us, do we not die? and if you wrong us, shall we not
revenge? If we are like you in the rest, we will
resemble you in that. If a Jew wrong a Christian,
what is his humility? Revenge. If a Christian
wrong a Jew, what should his sufferance be by
Christian example? Why, revenge. The villany you
teach me, I will execute, and it shall go hard but I
will better the instruction.
(3.1.1288-1307)

(Shylock by László Mednyánszky)

The Merchant of Venice, for all its wit and charm, is in this day and age a controversial play, because the murderous villain of the piece - Shylock - is a Jew. Not only does Shakespeare have a lot of his characters speak anti-Jewish insults, Shylock also defends his plot to kill the merchant, Antonio, in terms of justifiable revenge for Antonio's bad treatment of him because of his ethnicity and religion. In a way, Jewishness  - identity and defense - can be read as the root of the great evil that Shylock plans, and this emphasis on Shylock's Jewishness as such a major part of the story makes a lot of people uncomfortable - the play perceived by some as bigoted and ought not to be performed. Click here to read an examination of this kind of discomfort on "Blogging Shakespeare."
I strongly disagree with this view, for many reasons that I'll get into later. However, some productions, in an effort to overcome the what they see as the anti-Semitic implications of having a Jewish villain, focus on Shylock's speech that references Jews' shared humanity with Christians:

Hath not a Jew eyes? hath not a Jew hands, organs,
dimensions, senses, affections, passions? fed with
the same food, hurt with the same weapons, subject
to the same diseases, healed by the same means,
warmed and cooled by the same winter and summer, as
a Christian is? If you prick us, do we not bleed?....

In a performance that interprets this passage in a sympathetic way, Shylock can come across almost like a noble freedom fighter, struggling for equality in a harsh, cruel world. And this speech is undoubtedly crucially important: Shakespeare puts nothing in by accident, and this speech - which receives no contradiction - refutes any sort of anti-Semetic idea that Jews are somehow a lesser/separate form of humanity, monsters by nature (a very offensive idea! If this were Shakespeare's Shylock, I would agree that the play is anti-Semitic - but as we shall see, that's not what is going on.) However, this speech cannot, in my opinion, be used to make Shylock NOT a villain. It in fact proves that he is one: being exactly equal with the Christians in all his humanity, passions and sensibility, he makes a deliberate choice to embrace violence and vengeance, turning himself INTO a monster:
If a Jew wrong a Christian,
what is his humility? Revenge. If a Christian
wrong a Jew, what should his sufferance be by
Christian example? Why, revenge. The villany you
teach me, I will execute, and it shall go hard but I
will better the instruction.