History is written by victors of war.
Because the Autobots won the Great War, it is the Maximals who hold political power on Cybertron. This doesn't mean that the Predacons are enslaved or heavily discriminated against, it just means that there is a disbalance of political representation of Maximals in the Cybertronian government.
For example, the Australia is politically dominated by white men. This doesn't mean that people outside of this demographic are actively persecuted or discriminated against - nor is that to say that discrimination doesn't exist either, sadly it does - but it's no longer something that is actively tolerated or encouraged by the government. It was until 1969 which was the year that saw the abolition of the White Australia Policy and it was the Whitlam government which actively saw more policies acting to break down race and gender barriers, such as policies encouraging/enforcing equal opportunities and multiculturalism. But the fact remains that the majority of senators in the Parliament are still white males and that white men do have political dominance in this country.
"I'm a white male, age 18 to 49. Everyone listens to me, no matter how dumb my suggestions are!"
The Predacons are in a similar boat - politically under-represented. Of course, this is also partially the fault of the Tripredacus Council who intentionally sit on their laurels, pretending that they're working to gain more political power for the Predacons but in reality do bugger all - after all, the Tripredacus triumvirate are not truly loyal to the Predacon cause (they, Tarantulas and the Blentrons all serve their Dark Lord). This would be part of the reason why you have so many malcontent splinter factions within the Predacons, such as those led by Megatron, Galvatron and Magmatron - all getting sick of Tripredacus' inability to gain tangible results, rallying other frustrated Predacons to their cause and forming all these rogue groups. Which of course, fits in perfectly with Tripredacus' plan to keep the Transformers race disunited (because if they ever truly united they would pose a threat to Unicron).
I've analysed this issue more thoroughly in my fan-made character profile (and fictitious essay)
Dreadwave