I'll try to rephrase the question.
"Orthodox use liturgical worship. Protestants don't."
Sometimes some would mean low-church or evangelical or a special grouping of Protestants. Modify it as you need to. The point is, that's a belief or claim that I see often enough to wonder what people mean by it. Most protestants have ceremony and ritual; some of them wouldn't deny it, and some would, but they have those things nonetheless. Protestants have corporate worship. Protestants would argue that God is present, etc.
What makes Orthodox worship liturgical and Billy Bob Baptist Bible Believen church services not liturgical?
Is God not present at their services? Do you believe they don't have custom, tradition, or ritual observances? Are they not liturgical because they are not in the Church? Or what...? And how are those things related to a definition or description of liturgical? The aforementioned Baptist Church also doesn't have icons or pink rugs, but what does that have to do with "liturgy"?
And if any of these, then why are other groups, which are also not in the Church, which do not have the same customs, etc., sometimes said to have liturgical services?