The decision was part of a double blow from the Scottish Professional Football League on Monday, with Hibs handed another rearranged fixture in their already hectic December following the rescheduling of the visit of Aberdeen, which clashes with the cup final, for the 22nd of the month.
Hibs declared they were "incredibly frustrated" after being allocated 17,500 tickets for the circa 50,000-capacity Hampden when they take on Celtic on December 19, following "long intense discussions" with the SPFL.
The outcome left Ross "baffled" and he added: "Naturally you want as many of your own supporters in the stadium for a cup final, and also historically we have taken massive crowds to cup finals in recent times.
"The counter-argument to that is the semi-final attendance. I find that a really strange thing to take into account because the League Cup has never been one that attracted big crowds in semi-finals.
"It's baffling that we do not get that opportunity to take that allocation and Hampden never looks like a difficult stadium to segregate.
"I find it quite astonishing but it's about using it as a positive to galvanise us. And one thing I would say about Sunday is the 10,000 we had there made enough noise for 40,000 and we will hope that just under 20,000 people at the final will do the same."