Use an array to dynamically assign a variable name, then extract array data while avoiding eval

With bash 4.3 or later, you can declare a variable as a reference to another variable by saying declare -n varref. Here's an example code:

#!/bin/bash

declare -a read_only=(Alice Bob Charlie)
declare -a authorized_for_all_host_commands=(Dan Emma Fred George Harry Irene)
declare -a loc_NagiosUsersAll

declare -n role="read_only"
echo ${#role[@]} users
# yields "3 users"
loc_NagiosUsersAll+=(${role[@]})

declare -n role="authorized_for_all_host_commands"
echo ${#role[@]} users
# yields "6 users"
loc_NagiosUsersAll+=(${role[@]})

echo ${#loc_NagiosUsersAll[@]} users
# yields "9 users"
echo ${loc_NagiosUsersAll[@]}
# yields "Alice Bob Charlie Dan Emma Fred George Harry Irene"

Hope this helps.

[Edited] The following code is the modified version based on your latest post.

declare -a NagiosUserRolesAll=( authorized_for_read_only
                            authorized_for_all_services
                            authorized_for_all_hosts
                            authorized_for_system_information
                            authorized_for_configuration_information
                            authorized_for_system_commands
                            authorized_for_all_service_commands
                            authorized_for_all_host_commands )

function func_NagiosUserDataGet(){ # was load_data_tables
    local -a loc_CaptureUsersPerRole=""
    local -a loc_NagiosUsersAll=""
    printf "Loading users into the different tables.  \n"
    for role in "${NagiosUserRolesAll[@]}"; do
        declare -a $role="($( cat ${svnFilePath} | sed -n "s/${role}=//p" | sed  's/,/ /g' ))"
        printf "These users have the role ${role}:  "

        declare -n ref=$role         # copy the reference, not the contents of the array
        printf "${#ref[@]} users  \n"

        loc_NagiosUsersAll+=(${ref[@]})
#       loc_NagiosUsersAll+=" "
    done
    printf "Creating list of unique users.  \n"
    NagiosUsersAllClean=($( echo ${loc_NagiosUsersAll[@]} | tr ' ' '\n' | sort -u ))
    printf "Total users:  ${#NagiosUsersAllClean[@]}.  \n"
}

[Edited on May 12] The point is that the assignment to a reference should appear in the declare -n syntax. Otherwise it will yield an unexpected result. Here's the example:

declare -a arys=(ary_a ary_b ary_c)
declare -a ary_a=(a1 a2 a3)
declare -a ary_b=(b1 b2 b3)
declare -a ary_c=(c1 c2 c3)

# test 1
for role in "${arys[@]}"; do
    declare -n ref="$role"
    echo "${ref[@]}"
done
# => works properly

# test 2
for role in "${arys[@]}"; do
    declare -n ref
    ref="$role"
    echo "${ref[@]}"
done
# => does not work correctly

[Edited on May 15] Here's the modified verion which should work:

declare -a NagiosUserRolesAll=( authorized_for_read_only
                            authorized_for_all_services
                            authorized_for_all_hosts
                            authorized_for_system_information
                            authorized_for_configuration_information
                            authorized_for_system_commands
                            authorized_for_all_service_commands
                            authorized_for_all_host_commands )

function func_NagiosUserDataGet(){ # was load_data_tables
    local -a loc_NagiosUsersAll=""
    printf "Loading users into the different tables.  \n"
    for role in "${NagiosUserRolesAll[@]}"
        do
            declare -ag $role="($( cat ${svnFilePath} | sed -n "s/${role}=//p" | sed  's/,/ /g' ))"
            declare -n ref="${role}" # copy the reference, not the contents of the array
            printf "The role ${role} has ${#ref[@]} users.  \n"
            loc_NagiosUsersAll+=(${ref[@]})
            loc_NagiosUsersAll+=" "
        done
    printf "Creating list of unique users.  \n"
    NagiosUsersAllClean=($( echo ${loc_NagiosUsersAll[@]} | tr ' ' '\n' |
sort -u ))
    printf "Total users:  ${#NagiosUsersAllClean[@]}.  \n"
}

function func_NagiosUsersShow(){ # was show_all_users
    if [[ "${svnFileExists}" == '1' ]] ; then
        printf "You'll need to checkout a cgi.cfg file first.  \n"
        return 1
    fi
    printf "\nThese are the roles with their users.  \n\n"
    for role in "${NagiosUserRolesAll[@]}"
        do
            declare -ng ref="${role}" # copy the reference, not the contents of the array
            printf "These users are in ${const_TextRed}${role}"
            printf "${const_TextPlain}:  "
            printf "${const_TextGreen}"
            # printf "${ref[@]}  \n" # FAILS
            printf "${ref[*]}  \n" # => should work
            # eval echo '${'${role}'[@]}' # WORKS
            printf "${const_TextPlain}  \n"
        done
    printf "\nNow for a list of unique users.  \n\n"
    func_EnterToContinue
    printf "Unique users list:  \n"
    for i in "${!NagiosUsersAllClean[@]}"
        do
            printf "$i:  ${NagiosUsersAllClean[$i]}  \n"
        done
    func_EnterToContinue
}