Deleting a host deletes all host components first. This already reconfigures all the necessary sites.
At the end web-ui deletes host and again reconfigures config sites. This leads to unnecessary reconfiguration. For example deleting a host will reconfigure hive-site, webhcat-site, core-site etc if HIVE is present in the cluster but none of the hive component is present on the host being deleted which is not needed and creates unnecessary confusion.