The extradiction treaty for one. They want Hong Kong under their legal and administrative systems. Meanwhile the people in the street have made it abundantly clear they would rather have anything but that in downright "heretical" terms to the national mythologies.
I don't like the ill-fated extradition treaty either. But even if it did pass, with its narrow scope and all the strings attached, how exactly would that place Hong Kong under the Chinese legal and administrative system again?
The treaty is dead. The people still in the streets have other agendas that have nothing to do with rebelling against "assimilation".
> The people still in the streets have other agendas
Here is that agenda, also known as the 5 demands:
1. Kill the extradition bill. Done.
2. Retract use of the word “riot” to classify the protests.
3. Release and drop charges for protesters who have been arrested.
4. An inquiry into the widespread, well documented police brutality.
5. Universal suffrage.
In other words, they want their right to peacefully protest & vote for their leaders. To claim they have such rights already would be to ignore their words and their plight entirely.