Whether or not UCF is the "Best Team in the Nation", or not, no one - no one with any sense - would criticize that program for doing what it can to play the toughest schedule possible.
Like everyone else, the bulk of their schedule is dictated by their own conference membership. And you can only play the OOC games that the "other program" will agree to (and very few highly regarded teams are going to agree to a home-and-home with UCF - - - so getting their "home only" games requires them to look at lower level programs).
That said, here is who UCF DID schedule OOC over the last decade:
** Road Game
2008
Miami **
Boston College **
USF
2009
Texas **
Miami
Bowl Game - Rutgers
2010
NC State
Kansas State **
Bowl Game - Beat Georgia
2011
Boston College
BYU **
2012
Ohio State **
Missouri
Bowl Game - Beat Ball State
2013
Penn State **
South Carolina
Bowl Game - Beat Baylor
2014
Penn State **
Missouri **
BYU
Bowl Game - NC State
2015
Stanford **
South Carolina **
2016
Michigan **
Maryland
Bowl Game - Arkansas State
2017
Maryland **
Bowl Game - Beat Auburn
Personally, when I think of the "Best Team", my primary criteria is "Who would be the toughest team to beat"?, and - IMO - that is NOT UCF.
But, given the fact that there is no "settle it on the field" structure for college football, and UCF did everything that a championship team can be asked to do, they MOST CERTAINLY have as much right as anyone to call themselves "Champions".
And THEIR proclamations mean every bit as much - if not more - than the trumped up proclamations of the endless stream of sports media windbags, or some group of self-important assholes sitting around a buffet table.
So - good for them.