Why is it bad to call instance method in initializers

initialize-instance-method-example.rb

class Logger
  def info(*args)
    puts(*args)
  end
end

class Auditor
  def log(action)
    puts "Following action was performed: #{action}"
  end
end

class Destroyer
  attr_accessor :logger

  def initialize(logger)
    self.logger = logger
  end
end

class AuditedDestroyer < Destroyer
  attr_accessor :auditor

  def initialize(logger, auditor)
    super(logger)
    self.auditor = auditor
  end

  def logger=(value)
    super(value)
    auditor.log("Log assigned")
  end
end

AuditedDestroyer.new(Logger.new, Auditor.new)

# => initialize-instance-method-example.rb:31:in `logger=': undefined method `log' for nil:NilClass (NoMethodError)