It’s not a stereotype, so I would boil it down to creator preference.
What’s more, Himaruya has confirmed that Brittania (England’s mother) was a tsundere.
Source: Hetarchive (Bamboo Thicket, Eng trans., Sept 21rst, 2011).
*Just want to clarify that I made a mistake in the past, back when I first began posting last year. Brittania doesn’t have an official appearance. The women surrounded by Rome in the We’re Shipwrecked strip haven’t been given official statuses as characters. Since Rome was known to always be surrounded by beautiful women, that’s what they remain as.*
Ellawritesficssometimes 