When user uses CqlBulkOutputFormat, it tries to stream to all the nodes in the token range, which includes the dead nodes. Therefore, the stream failed. There was a design in C* API to allow stream() method to have a list of ignore hosts, but it was not utilized.
The empty-argument stream() method is called in all existing versions of C*, i.e.
in v2.0.11, https://github.com/apache/cassandra/blob/cassandra-2.0.11/src/java/org/apache/cassandra/hadoop/AbstractBulkRecordWriter.java#L122
in v2.1.5, https://github.com/apache/cassandra/blob/cassandra-2.1.5/src/java/org/apache/cassandra/hadoop/AbstractBulkRecordWriter.java#L122
and current trunk branch https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/hadoop/cql3/CqlBulkRecordWriter.java#L241