IRule not working - sytnax error or something else?

Try this:

 
when HTTP_REQUEST {
switch -glob [string tolower [HTTP::uri]] {
"*XXX*" {
if { !([matchclass [IP::client_addr] equals $::XXX_access_list]) } {
                HTTP::redirect https://MyXXXUnauthPage.com
            }
        }
        "*YYY*" {
            if { !([matchclass [IP::client_addr] equals $::YYY_access_list]) } {
                HTTP::redirect https://MyYYYUnauthPage.com
            }
        }
        "*ZZZ*" {
            if { !([matchclass [IP::client_addr] equals $::ZZZ_access_list]) } {
                HTTP::redirect https://MyZZZUnauthPage.com
            }
        }
    }
}

Your not comparison (can also be expressed by "!"), needs to be inside of your if statement and needs to be applied to the entire comparison.

Comparison: [matchclass [IP::client_addr] equals $::ZZZ_access_list]

Comparison: !(results of first comparison)

Result: if false, do this....