The Royals were hammered pillar to post by the Gunners to remain at the foot of the table with Kebe criticising the club for not purchasing any key players after they took out the Championship title last season.
But McDermott believes Kebe's comments were born out of frustration because the winger is so passionate about succeeding at the Madejski Stadium.
"What it shows is that Jimmy Kebe, like every other player here, cares. He really cares, we all care," said the Royals boss.
"Jimmy cared last season when he signed a new contract and he wanted the club to get promoted, which we did.
"Jimmy Kebe loves his football, he loves this club, he loves working for us and he's very much part of what we're trying to do here.
"The owner (Anton Zingarevich) cares, the chairman cares, I care, the fans care and Jimmy Kebe cares. All our players want the club to do well, first and foremost.
"Let's hope a 'good Championship side' can get the points we need to get to wherever we need to get to.
"I'd like to think that we have enough decent players and that we can get the points we need. The summer's gone and all we can do is affect what happens now."