The review isn't factually incorrect.
If you choose to block all anonymous calls with TrueCall, it blocks ALL anonymous calls including from the emergency services. It even says so in the manual.
If the reviewer bought TrueCall to block anonymous calls he is correct but shouldn't moan too much as its working as intended.
To quote my TrueCall Reference Guide (c) 2009 (page 7-8) -
Anonymous Caller Reject
If you have Caller ID on your phone line, you can tell trueCall to
reject all anonymous callers - all callers who withhold their calling
number. It plays them the announcement :-
“You have withheld your calling number so I cannot connect you”
and doesn’t ring your phone. Anonymous Caller Reject only blocks
calls where the caller has withheld their number. If the caller’s
number is not available for any other reason - for example it is an
international call - then Anonymous Caller Reject will let it through.
WARNING: Anonymous Caller Reject is very effective at blocking
malicious calls, but be aware that it may also block calls that you
want to receive. Doctors, hospitals, the Police, government
organisations and many companies routinely withhold their