It is definitely meant to be like that. The move Kc7 forks the two rooks and yet, it is not the best one because it doesn't put you any closer to mate. Some times getting rid of pieces is good but in this case, if there's mate in 4-5 moves or perhaps a forced Queen sacrifice then we should always try and do that.

The solution which I found after trying out the knight move, is as follows:

Ignoring an obvious fork and then sacrificing a Queen to achieve mate in 3 is quite difficult, especially because most players don't even see this sequence, I myself missed it completely.