Why the url of a flight has to include departure time?

Hello:

I wonder why flightaware requires the departure time (or something like that) in the URL for a specific flight. For example, 2110Z in
https : //flightaware.com/live/flight/AMX228/history/20191029/2110Z/MMMX/MMGL

That only makes almost impossible to find a past flight, since departure time changes for each flight, and very often that “magic time” is NOT even the scheduled / actual departure time. So we have to guess it.

If the reason is because some flights have several legs, it would be enough supplying the origin/destination, without the “magic time” For example, the ideal URL for the example flight would be:
https : //flightaware.com/live/flight/AMX228/history/20191029/MMMX/MMGL

I hope you can remove that annoyance!!