Pedant mode "on".
I think I'd bet good money that the term CATOBAR derived from the STOBAR description bandied around in the late 90s to describe how Kuznetsov operated, where the B always stood for "But". As GK points out, "barrier" has always had a far different connotation at sea.
The reason that CATOBAR was invented as an acronym was that until recently, the commonly used description of catapults and arrester wires aboard ships was CTOL. This was used throughout the 70s, 80s and 90s and everyone understood what it meant. The CVF (even CVSG(R)!) concept papers throughout the 90s all referred to CTOL ships.
However, then came JSF, where in order to differentiate between the Air Force, USMC/STOVL and USN versions, people started using, CTOL, STOVL and CV respectively. This confused the issue, particularly given that CTOL and STOVL referred to launch and recovery types, but CV referred to the "host platform". Hence someone somewhere decided to invent a new acronym - CATOBAR - which really should have been CATAAR, with the first A standing for "and". However, this sounds like a bad cold, so that probably got binned.
To go all Tom Jones on folk, it's not unusual these days to find loopy new acronyms, or even old ones corrupted. Leafing idly through a defstan the other day I discovered that CVS apparently stands for "Carrier Vertical Strike", which must be a surprise to all those who for decades thought CVS stood for Anti-Submarine Carrier, or occasionally "Support Carrier". I did once read a report that suggested CVS stood for conventional submarine, but it was written by someone "a bit special", so not particularly surprising.
Pedant mode "off".