I think I have a solution to the problem. Its a simple matter of balance. Chronopolis was based on an alternate future (happy Chronoland Keystone timeline), as was Dinopolis (Happy Chronoland Reptite timeline). Now, both Poli (plural of polis) were massive amounts of 'data' (people and objects), which would cause a huge disruption in time if moved (time crash, dead sea, etc.). The laws of time would require a seperate time crash along with the main one to balance the continuum. Similar to this:
Imagine time a scale. The actual scale itself is the continuum, and the cups for weighing are the Poli. If you add a large amount of weight to one side, the other would tip. If the imbalance is large enough, it could even break the scale. Now, assume you add, oh, maybe 5 pounds (Chronopolis) to one side. Time wants itself to remain as equal as possible, so you must add 5 more pounds (Dinopolis) to the other. Now the scales have been equalized.
So, Dinopolis HAD to be pulled back to balance the shift caused by Chronopolis.
BUT WHAT THE HELL DOES THIS HAVE TO DO WITH THE RED GATE?!?!?!?!?