According to the Whites boss the club did all they could to try and keep the Colombian winger but had to accept the contractual complexities involved and agree a loan deal with Bournemouth.
Sinisterra's exit was confirmed after the 11pm deadline on Friday night as Leeds and the Cherries came to terms on a swap that brought Jaidon Anthony the other way.
Farke called the loss of a player who could have dominated in the Championship a 'tough reality' but one Leeds had to live with.
"I'm always open and honest and I praised him since my arrival," said Farke.
"We spoke about him being an outstanding dominating player on this level. We tried everything in order to keep him but his contractual situaiton was complicated and in the end sometimes you have to accept a tough reality. He went this way and is at Bournemouth right now. We have to accept such a tough reality and adapt to it."
A number of the summer exits at Elland Road were expected or even welcomed by the club but Sinisterra followed in the footsteps of a number of players who Leeds wanted to keep.
Max Wober, Jack Harrison and Tyler Adams all made it clear that they wished to depart, although they at least did so with time to spare in the transfer window. Sinisterra trained at Thorp Arch on Friday before his move began to develop ahead of the late-night deadline.
Farke was in no mood to disparage those who left but admitted he did not envisage things panning out quite as they have.
"It's not my style [to criticise them]," he said.
"We spoke about a few players, great lads with really good quality. I wouldn't have predicted eight weeks that the squad would look like this and I'm pretty happy with my squad. I'm experienced enough to accept the reality and work with what we've got. There's no feeling sorry for some losses. The players here get my full attention and backing. We try to get the best from our squad right now."
What softened the blow of Sinisterra's loss, to some degree at least, was the arrival of Anthony, who boasts Championship and Premier League experience. However he is not, Farke pointed out, a like-for-like replacement.
"I have to praise the key people in our club, sometimes when you lose such a crucial player with a few hours to go you can feel sorry for yourself," he said.
"We tried to find the best possible replacement for him. In Jaidon Anthony he's a proven Championship player, many good performances for Bournemouth. He has started the first games on Premier League level and played many games. He's desperate to be here, he's still at an age where he can improve. You can't compare them. He's still young. Luis Sinisterra is a proven international player. Jaidon is in, we're all happy."
With five games of the Championship game gone and Leeds in 15th on six points, Farke finally knows the squad he will have to work with until January at least.
He's unconcerned about where they find themselves now, thanks to his past experience, and hopeful of better things to come.
"It will be such a long season," he said.
"With Norwich the first time we were promoted it was a club record, over 90 points. After the same games [as now] we had fewer points than [Leeds] have. Pukki was praised as an unbelievable goalscorer, he was there with zero goals at this point. You don't have to be where you want to be after five or 10 game days, it's where you are after 46. We have a proper group and something to build on. I'm quite sure we'll find some times when it's easier to find the back of the net."