That’s a question loaded with the potential for misunderstanding.
Let me ask you, what specifically do you mean by “wrong”, “celebrate” and “Passover”?
Covenantally speaking, what the Bible identified as “Passover” ended 2000 year ago when the Antitype of Passover, Jesus Christ, the Lamb of God, appeared in human flesh to take away sins of His people.
Passover was a type and shadow of the reality that was to come. It was part of the old covenant which Hebrews speaks of decayed and fading away (Heb. 8:13).
Today we find Jews who deny the fact that Messiah as has come in the flesh who still go about trying to “celebrate Passover” according to the rabbinic traditions that were developed in the aftermath of the destruction of the temple in AD70. It has become an unbloody celebration because they have no alternative. But it fundamentally denies who Jesus Christ is and what He did on the cross for His people.
Most Christians have no regard for Passover since they view it as part of the old covenant system that was temporary and fading away after the time of Christ. The priesthood, sacrifices, dietary laws, clothing laws, etc were all part of that older, temporary system.
However, within Christianity I can identify at least two groups that still have some regard for “Passover”. One group regards the identification with Passover not so much as a religious rite, but as a cultural or educational matter. For them it is a teaching tool, like these “Christ in the Seder” plays that are common around that time of the year. Most of these folks see no religious significance, i.e., God is neither pleased nor displeased with their activity. If they were to stop doing it tomorrow for whatever reason, they would have no problem since they are not bound by Scripture to observe the rite.
The other group is the one that does it for purely religious reasons. They believe God has authorized them to make whatever modifications necessary from the strict laws given in the Scripture regarding how to keep a proper Passover, and, further, they believe God is pleased with their attempts to keep this ersatz “Passover”.
It is this last group that I have difficulty with since I cannot justify their actions from Scripture. They misunderstand the nature of the covenant, and see continuity were none exists in the Bible. They even go so far as to encourage non-Jews to participate in their ersatz ceremonies.