There are two answers to this question.
The first answer is that the word “Easter” has become established in Christian usage for the events of Christ’s death and resurrection which happened at the time of the Jewish Passover. So the Christian reference to Easter emphasizes the Resurrection Sunday on which Christ was raised by God, rather than “Passover” which emphasizes the sacrifice of the Passover lamb. This starts at sunset on Friday and ends at sunset on the Saturday following – so including two full Saturday Sabbaths at either end of the Jewish Passover.
The second answer is in the chronology. The Jewish calendar and the Christian calendars are often slightly out of step. For example in 2017 the Jewish Passover was 10-18 April, but the Christian Easter fell on Sunday 16 April (a week late), yet in 2018 Passover was 30 March-7 April, while Easter Sunday was 1 April (coinciding with the Jewish calendar). Since both Jewish and Christian calendars are lunar and the days of the week are the same there should in theory be no dislocation, but historically the Christian calendar is an attempt to harmonise solar and lunar calendars, fixing Easter as the first Sunday after the first full moon after the vernal equinox (21 March). In addition there is more than one Christian calendar so the Protestant and Catholic Easter typically falls a week before the Greek and Russian Orthodox Easter. There is some debate too about the Jewish date, but in general it can be assumed to be more accurate.
Another issue relating to the difference between Easter and Passover is that while the Old Testament commands Jews to observe the Passover, the New Testament regards both animal sacrifice and the Jewish feasts as having passed away.
16 Therefore let no one pass judgment on you in questions of food and drink, or with regard to a festival or a new moon or a Sabbath. 17 These are a shadow of the things to come, but the substance belongs to Christ. (Colossians 2:16-17)
Instead Paul focuses Passover on Jesus as the Passover (the word lamb is added in modern versions):
“Cleanse out the old leaven that you may be a new lump, as you really are unleavened. For Christ, our Passover [lamb], has been sacrificed.” (1 Corinthians 5:7)
And Paul connects that with the weekly taking of bread and wine to remember Christ, such as “on the first day of the week, when we were gathered together to break bread” (Acts 20:7, 11). So for the Christian while Easter is a significant time of year because the date – approximately correct as the date of Passover – does commemorate Jesus’ death and resurrection, and therefore Easter Sunday is certainly not the one Sunday a year when Christians should not remember the death of Christ. However, the example in the New Testament is of a weekly “Passover” meal, such as 1 Corinthians 5:7, not only once a year.