This is how evolution works. People often imagine some sort of logical system to it, but it really is just random mutations all over, with the advantageous ones propagating. There were probably a bunch of tigers with various odd colors or patterns at some point due to random mutations, but those evidently were less useful for hunting and reproducing than how they look now, so they died out in competition with the known variants.

But deer vision is immutable god creation. Checkmate.

Maybe the orange color happened to coincide with the patterns that worked best. Had their prey been able to see the orange tint it would have worked against the tiger, but since they can't it was allowed to flourish with that pattern. If true at all, it's a bit of a dead end since a mutation for the prey to begin seeing orange means tigers have narrowed into that pattern dependent on the color.