To save a bit of repeated task executions, if you plan to do a lot of them in one swoop, you can do something like
action parameter query "UserList" with description "Enter semicolon-delimited usernames to remove" and with default value "user1;user2"
delete __appendfile
appendfile { concatenation "%0d%0a" of ("net user %22" & it & "%22 /active:no") of names of local users whose (name of it as lowercase is contained by set of (substrings separated by ";" of parameter "UserList" as lowercase))}
delete RemoveUsers.cmd
move __appendfile RemoveUsers.cmd
waithidden cmd /c RemoveUsers.cmd