I’m struggling to understand this argument. It seems to argue about what sort of comparisons one ought to input, not how the comparison should be used.
You can provide whatever binary function you want, not sure why the abbreviation should dictate that. <= is accepted. The way I read it is
lt=foo:ais considered less thanbiffoo(a, b)is true.
You could use lt=(>) if you like, or even lt=(x,y)->rand(Bool).