I think he's saying that datacenters would not have water sprinklers and would instead use Halon fire extinguishers.
He's wrong and you/Wikipedia are right, BTW. Halons were banned in 1994, before datacenters became commonplace. Argon and other inert gas fire suppression systems (of which Halon is one, but a banned one) are used instead.
The op's a bit outdated, but not completely wrong. Even now a lot of data centers use various halon replacements rather than Argonite, though there are a number of different gaseous fire suppressants used in data centers these days.
The last data centre I worked in certainly had water sprinklers too.
The gaseous system was one-shot. If the fire continues or restarted, or another fire occurred before the system was recharged, water sprinklers would save the building.
Redundant systems. Of course, some data centres probably have redundant gaseous suppression too.
He's wrong and you/Wikipedia are right, BTW. Halons were banned in 1994, before datacenters became commonplace. Argon and other inert gas fire suppression systems (of which Halon is one, but a banned one) are used instead.