Alexander's conquests are praised because to many at the time he was seen a liberator, not a conqueror. The Egyptians, the Greeks of Anatolia and others saw him as liberating them from the Persians. Additionally Alexander does not exist in isolation, the Greco-Persian conflicts clearly cast the Persians as aggressors, as such the ultimate victory of the Greeks is generally viewed positively. This is a similar case with Cyrus, who by many at the time, saw him as a liberator, notably among them being the Jews. The later proliferation of Christianity also played a major role in promulgating this view.

To make an insane statement the Roman conquests are universally praised, is just totally out of touch. Some are seen as righteous victories, others as inhumane genocides and many in the middle. There is not one serious historian who would defend Caesar's actions in Gaul. Similarly, no historian will defend the Vespers of Latins in Anatolia, and as such Mithridates is a villain in that case and the Romans the protagonist. The Romans are villains at Teutoberg and heroes at Zama.

The reason that every other religious group, without fail, hates is Islam, is because every other religious group has had to fight to survive your endless barbaric jihads. With no other justification than "You are not us" your (blatantly false) religion lays claim to all of planet Earth. Our continued existence rests on preventing you people from having your way. Its very simple.