Unlike Jews and Muslims, Christians worship holy spirit and Jesus pbuh.
Yes, but contrary to whatever Muslims think, we don't worship Jesus and the Holy Spirit alongside God. We say that Jesus and the Holy Spirit ARE God. We worship the Father, Son and the Holy Spirit, One God, as the Roman Catholics and Antiochian Orthodox say during every prayer.
They also worship saints and virgin Mary pbuh.
Not so. We give them respect the same way that Muslims honor Muhammad, but they are by no means worshipped.
So they are clearly Polytheists.
No, we are just monotheists with a more complex view of God.
Because we have a saying from Umar r.a. He said: I know you(stone) cannot benefit me nor harm me, if the prophet pbuh didnt kissed u i would never have kissed u.
So the stone is just symbolic direction of prayer. It has no power at all.
It sure doesn't seem like that to any non-Muslim. Do you see how the Muslim attitude towards the Kaabah is the same as the Christian attitude towards our icons and our statues?
But christians say Mary can hear us and forgive our sins!
No one can forgive sins except God alone. This is and has always been Christian teaching. The only reason that the Saints can hear us after death is because they have received the grace from God to be able to do so, for all are alive in God (Luke 20:38)
They say the same about saints
I don't know if Muslims ever do this, but we Christians pray for one another regularly. As Saint Frankenstein said, we believe that Jesus shattered the boundaries between life and death. The Church on Earth is connected to the Church in Heaven, and so the Saints are able to pray for us, just as they did when they were alive.
This is because Jesus Himself is God.
So that is clearcut idolatry.
If you were right about Christianity, then you would have a point. As it is, you only know a caricature of what we Christian actually teach and practice.