Is Islam an evil empire?
Yeah...
Is Islam an evil empire?
No, but Islamism (radical, totalistic/totalitarian Islam) is.
Your analogy is like saying the evil nature of the Soviet Union was solely the consequent of its being a Russian empire, and therefore that all Russians, and everything Russian, is suspect. (Analogy being to: All of Islam is suspect, as are ALL Muslims, because Islamism is an Islamic movement.)
Now there may well have been (indeed I think there were and are) cultural characteristic of Russia that facilitated the development of the communist evil.
Likewise there may well be (indeed I think there are) characteristics of Islam that have facilitated the development of violent, totalitarian movements within it, and the grossly inadequate marginalization thereof.
But this does not mean that Islamism is a necessary or universal consequence of being Muslim, any more than communism (or being a communist) was a necessary or universal consequence of being a Russian.
There are many Muslims who are consciously and absolutely opposed to the totalitarian movements within Islam. All I'm asking is that we not nullify them, and undermine their efforts, and marginalize them thereby putting them at even greater risk, with the bigoted lie that they don't exist.