There is no "Uninstall Operation" option is there on the console for Web Terminal Operator. Instead, "Delete ClusterServiceVersion" option is there. Please correct the documentation[1].
[1] https://docs.openshift.com/container-platform/4.13/web_console/web_terminal/uninstalling-web-terminal.html#removing-web-terminal-operator_uninstalling-web-terminal

Always

1. Install Web Terminal operator in OCP 4.13
2. Then try to uninstall it following the documentation - https://docs.openshift.com/container-platform/4.13/web_console/web_terminal/uninstalling-web-terminal.html#removing-web-terminal-operator_uninstalling-web-terminal
3. Refer points 3 and 4, you won't find "Uninstall Operator" option. Instead, "Delete ClusterServiceVersion" option is there on the console, which make the statements 3 & 4 of the document incorrect.

"Uninstall Operator" is mentioned in the document

"Delete ClusterServiceVersion" should be mentioned in the document