We had a lad with a Polish surname who was just known as 'Trotsky'and another lad had bad acne as a teenager and spent the next 22 years being called 'Spot'. Both refuse to this day to answer to their 'proper' names
Asked why? 'Cos he'd blow any fúcker up mate'
And a WO2 with a double barreled surname jocularly referred to -out of his hearing- as Smiff-Emptyhead.
Also a lad from Nottingham of Ukrainian heritage universally known as 'Ski'.
In answer to the OP's rhetorical question - it's cos they're pongoes. Navy does better nicknames, some of which go back centuries.
Check numerous threads on the dark blue side.
When I was in the RNR, my unit boasted one 'Windy' Gale, one 'Shiner' Wright, one 'Tansy' Lee and several 'Sharkey' Wards. And a rail thin chef - inevitably known to all as 'Split-pin'
I also served with a guy called Lammiman, known throughout the ship as 'Doc' - refers to an early Medical Director General (Navy) of the same name. Tall skinny lad, liked to wear a frock coat when he went ashore.
On the same short draft, a big intimidating killick stoker called 'Blood' Reid - he being fae Glasgow.