It's wasn't. They also have been known to regularly sing:To be fair to the mancs, by the time of Hillsborough they had endured many years of that charming little ditty (To the tune we know as "Who's that team they call The Arsenal") being sung full throttle by thousands of scousers, with words recalling Busby and his boys dying in the snow..
Their post-Hillsborough repost, so far as I recall, was all the more devastating by being restricted to "Where's your famous Munich song?".
"Who's that standing at Hillsborough
Who's that turning fucking blue.
It's a Scouser and his mate, getting crushed on Hillsborough's gates.
And they won't be singing Munich anymore"
Shameful. But then we also have a minority of arseholes in our fans base that make the hissing gas chamber noise at the scum.