Why are the TFs on Earth? Each movie gives a different reason. The Allspark crashed here? The Fallen is here because of Energon and built some kind of harvester? Sentinel crashlanded here / planned to meet Megatron here / tricked OP into following him here to set up spacebridges, teleport Cybertron here, and turn us all into slaves? Help me.
Yes, I could bash these movies for their nonsensical plots, obnoxious performances, and the TFs being reduced to background fodder, but, God help me, I love these movies. That's all due to my love of love of G1 TFs going back to 1984, the outstanding CGI, Bay's visuals and action, and Peter Friggin' Cullen.