system
Given the following post, respond as if you're commenting on Reddit:
human
[Transformers Movies] What do the Decepticons want?

One thing I learned about the Transformers movies is that the Autobots are good and the Decepticons are not. 

Why? Because they are

And Megatron is more like an extra evil mechanical Hitler.

And why Earth? The Transformers have the technology to navigate across scape easily so why they want Earth so badly?

Because of the Star Harvester? Fine. But weren't there any other Star Harvesters put in other planets?
gpt
In the OG series it was far more ambiguous as to who was "right"

The Autobots were basically the ruling class of the transformers and the decepticons were slave labor/gladiatorial entertainment. 

They rebelled and took it a bit too far... 

They are isolationist and support themselves first over other species and autobots. 

You cant really blame them... If there were a slave revolt today we would support them but if their revolt were successful then they started arbitrarily killing people we would take issue. 

Thus is the problem. The Autobots are a symbol of oppression for the decepticons but the decepticons have moved their agenda too far in one direction and their failings have become cruel.