what is reason for this design of weapon swap?

I honestly think this is dumb design, anyone else?

if I wanna lock main hand sceptre from set 1 in set 2, and use together with martial weapon (so I can leap), it will not let me equip martial weapon in off hand because it will force swap so that martial weapon is main hand, and sceptre is off hand

however, if I try to put sceptre from set 1 in offhand, then it will not let it stay this way with focus, because it will auto move focus to off hand...

so that, effectively it becomes impossible to use sceptre+focus in swap 1 and same sceptre+martial weapon in swap 2, effectively having to micro it all time or carry 2nd weapon that may be very expensive

why like this? to me, it does not make sense at all

Scepter can be used only in offhand if you use it with martial or caster weapon.

You can use Scepter in main hand only with Focus.