Google Apps Script:

function myFunction() {
var maxRows = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet().getLastRow();
var users = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet().getRange("A2:A"+maxRows).getValues();
var eventId = "";
for (var i = 0; i < users.length; i++){
try{
Calendar.Events.remove(users[i], eventId);
SpreadsheetApp.getActiveSpreadsheet().getActiveSheet().getRange("B"+(i+2)).setValue("EVENT REMOVED FROM USER'S CALENDAR")
}
catch(e){
SpreadsheetApp.getActiveSpreadsheet().getActiveSheet().getRange("B"+(i+2)).setValue("EVENT DOES NOT EXIST ON USER'S CALENDAR")
}
}
}