The SDC doesn't expose "Hive user" on the Hive components because the connection is done using JDBC and not Hadoop-native RPC.
With HDFS/HBase and other native RPC mechanism, there is exactly one way how a user can and should specify the do-as user (e.g. what user should be impersonated). There is no such standard on JDBC - each driver has it's own way how to specify impersonation. For example:
1) For the bundled Hive JDBC Driver
A user needs to specify the following JDBC property: "hive.server2.proxy.user" which is covered in docs:
2) For the Cloudera JDBC Driver, a user should use the DelegationUID property instead which is covered in a different doc:
A user needs to read the documentation of used JDBC Driver to figure out how impersonation should be configured.