Because Memorial Day honours those killed in wars and Jehovah's Witnesses do not agree with fighting.
Jehovah's Witnesses take bible law seriously. Jesus commanded his disciples in Mathew 5: 44 to "Love your enemies". Jehovah's Witnesses believe it would violate bible principles and Jesus command to kill or participate in any operation or effort to kill people.
Matthew 5: 9 "Blessed are the peacemakers: for they shall be called the children of God." -- American King James Version
"They will have to beat their swords into plowshares and their spears into pruning shears. Nation will not lift up sword against nation, neither will they learn war any more" (Isaiah 2:4).
Americans and Canadians both celebrate Memorial Day or Remembrance Day.
The only country that celebrates memorial day is the U.S.
Jehovah's Witnesses do not celebrate Presidents day.
The modern day history of Jehovah's Witnesses started in the United States.
no
No, because they are Jehovah's Witnesses and they do not celebrate Mother's Day.
all regions celebrate memorial day
solders
In 2013, Jehovah's Witnesses' Memorial of Christ will be commemorated after sunset on Tuesday, March 26, 2013. ("Our Kingdom Ministry", December 2011, ©Christian Congregation of Jehovah's Witnesses, page 4)Jehovah's Witnesses also schedule a "Special Talk" during "the Memorial season", on the regular day of each congregation's regular weekend meeting. The Special Talk is almost (though not always) scheduled for a date AFTER that year's Memorial, so it seems unlikely the Special Talk will be Sun, Mar. 24, 2013 (two days before that year's Memorial).
The last Monday in May.
Does any religion?
No, Memorial Day is a national holiday in the United States. It is not celebrated in other countries.