Hint's from other Ancestry Trees have to be turned off in the user's Ancestry Account. Log in to you're Account using your Browser (not RootsMagic), select your Tree and have a look at the options under "Manage Tree".
The Census Hints may be a bit more problematic to handle! For some unknown reason, Ancestry has never used "Census Events" for auto-recording Census data even though it could, because Census Events are supported by Ancestry (and FTM). Instead it automatically uses "Residence" Facts. So, if you use Census as most non-Ancestry/FTM users probably do, you have an immediate conflict. i.e. 'Hints' highlight that 'new' Residence Sources are available but cannot recognise that a Census Event already exists in RootsMagic because Ancestry doesn't use/reference that data field (correctly).