After tapping the comment you want to hide, tap the "!" icon in the bottom-right corner of the popup screen, and tap Block to block the user.
By blocking the user, all later comments by the user will be hidden.
Your comments will also be hidden from that user.
Note: The same effect will apply if you are a collab guest.
You can also report comments by tapping the comment you want to report by tapping the "!" icon in the bottom-right corner of the popup screen, and tapping Report.
Someone on our team will confirm the message contents, and if it goes against our terms of service, will decide what actions will be taken.